Buddhism in Sri Lanka belongs to southern Theravada Buddhism. It is said that in the 3rd century BC, it was introduced by Mahinda, the son of Ashoka king of India. Because its classics are inherited in Pali, it is often called Pali Buddhism in modern times.

In order to welcome moshanda to Sri Lanka for missionary work, King shivananpiye Tisha built the "great temple" (MAH) in the capital, arnuradhapura ā vih ā ra)。 At that time, it was the only center of Theravada Buddhism. Moshengtuo founded the great temple sect here. In 28 B.C., King vadojarmani abaye succeeded to the throne again. In order to repay the help given by the elder mahatisha during his exile, he built a new temple in Wuwei mountain as the missionary stronghold of mahatisha. Mahatisha built Wuwei mountain temple sect (also known as JieXi sect) together with the Indian monk Faxi. In the 4th century, elder sagali founded the zhiduolin Temple sect in the zhiduolin temple, also known as the Nansi sect. About the early 5th century, the above three schools went hand in hand. During the reign of King agalputi at the end of the 6th century, due to the royal family's support for the great temple sect, the power of the once dying great temple sect was revived again, and the other two factions belonged to the great temple sect.
At the beginning of the 7th century, under the rule of dadoyudhidi Shah I and his successor Gaye II, it was time for Xuanzang to study in India. According to what he heard in South India, Xuanzang described in the records of the western regions of the Tang Dynasty that the king of Sri Lanka did not believe in Buddhism, destroyed Buddhist statues and temples, and more than 300 eminent monks fled to India. According to Chinese historical records, in the first half of the 8th century, Sri Lanka once worshipped Mahayana and esoteric Buddhism was particularly prosperous. At that time, Vajra Chi, an Indian monk who went to China, preached the secret Dharma in Sri Lanka; His disciple Bu Kong also learned the secret Dharma from him and Puxian Ajara pear in Sri Lanka. Esoteric religion is not only supported by the royal family, but also popular among the people. Since the 10th century, Theravada Buddhism has been dying in Sri Lanka, and it is difficult to make up for the number of rated monks required for formal Buddhist ceremonies.
In the second half of the 11th century, King vijayabaku ascended the throne and sent envoys to Myanmar to welcome eminent monks who are proficient in Sanzang to Sri Lanka to rebuild Theravada Buddhism. Since then, other factions have gradually disappeared. However, due to frequent domestic and foreign aggression, from the end of the 12th century to the middle of the 13th century, the throne of Sri Lanka was occupied by foreigners, the capital was destroyed, and Buddhism was also destroyed. It was not until the meeting of the Buddhist order presided over by the monk King Dharma Jiedi II in 1395 that Theravada Buddhism appeared a new situation again. However, the Portuguese colonialists invaded in 1506. While promoting Christianity, they attacked Buddhism. Many temples were destroyed and monks were forced to convert. King vimaroda mosuriya, who ascended the throne in 1592, had to invite Myanmar Buddhist elders twice to revive Theravada Buddhism in Sri Lanka. Later, King Sri vijayaro jajisingha, who succeeded to the throne, welcomed the Buddha Dharma from Beigu, Arakan in Myanmar and ayucha in Siam (now Thailand). Siam sent Buddhist scriptures and statues that Sri Lanka did not have, and sent many elders to teach precepts, which gradually revived Theravada Buddhism.

After the revival of Theravada Buddhism in Sri Lanka with the help of Myanmar and Siam, it is divided into three factions: 1. Romana sect, that is, the system built by Buddhist elders invited from Myanmar in the 11th century. 2. Siamese sect, also known as youpoli sect, is a system invited from Siam in the 18th century. 3. Amoropro sect is a system in which some Sri Lankan Buddhists at home, because of their low social status and their monks are unwilling to give precepts, went to Ramallah in Myanmar in 1802 and returned after receiving precepts from local elders. The three sects did not contradict each other in religious theory, but the commandments were slightly different, so they lived in harmony until today.

At the end of the 19th century, Sri Lanka launched a Buddhist reform and revival movement. In 1880, major Alcott of the United States and Mrs. Blavatsky of Russia first established the Theological Society in Colombo to promote the revival of Buddhism. After that, damopolo founded the Maha Bodhi society in India, explored and protected Buddhist relics, edited Buddhist scriptures, published publications, publicized Buddhism at home and abroad, and established branches, making the activities of the Maha Bodhi society a broad Buddhist Revival Movement. After Sri Lanka's independence in 1945, the government regarded the revival of Buddhism as an important part of restoring national culture, established various Buddhist societies with secular nature, founded Buddhist teaching, edited and published the Encyclopedia of Buddhism. About 74% of Sri Lanka's population is Sinhalese, and about 94% of Sinhalese are Buddhists; There are more than 5600 temples and about 20000 monks in China.

The Sutra of Theravada was unwritten. 200 years after Buddhism was introduced into Sri Lanka, the oral Buddhist scriptures began to be recorded in words. The existing Sri Lankan Theravada classics are composed of laws, classics, on the three Zang, the notes to the three Zang and the classics outside Tibet. In the first half of the 5th century, India's Buddhaghosa came to Sri Lanka to rewrite the Sinhala notes of the three Tibetans of Theravada Buddhism into Pali and ease them in detail. He also wrote the theory of pure Taoism to discuss the outline of the Theravada doctrine preached by the great temple sect.