The objectives of this  thesis  were : 1) to  study  the biography of  King  Pasendikosala that appears in the scriptures of Theravada Buddhism,  2)  to  study role of  King  Pasendikosala on maintaining Buddhism    and 3) to  study King Pasenadikosala’ s activities applied in the today's society. This  research  was  a  qualitative  research  focusing  on  studying  documents by  surveying the  primary  level data  from  Canon and  commentaries  and  the secondary  level data from  academic  textbooks,  documents  and  related  researches.

The results of this study were found that in previous life, the King Pasendikosala was born to be Suttha Manapa. He gave a lotus and the sun blocking fabric to the Buddha in the Gohna kamana period and had a desire to be the Buddha. The Gohna kamana Buddha had predicted that he became Thamma Rajha Buddha. When the Pataragaba passed, the King Pasendikosala was Brahmin, respected the local religious culture and later respected Buddhism.

He worshiped the Triple Gem for life forever. He had age as same as the Buddha, and he was relatives with the Buddha. He was extremely grateful to the Buddha.

For its role on maintaining the Buddhism, King Pasendikosala was interested in the sponsoring by the requisites to the Buddha. He is a model for people in giving Amisadana, building the Monk’s cell. When he performed his duties perfectly, he communicated with the Dhamma. As a result, it made many Suttas concerning King Pasendikosala in Kosala Samyut.   He involved in providing Vinaya in Buddhism. 

The King Pasendikosala had many good activities, and he performed according to Ethic principles in Buddhism. As the leader of the country; he used the ten Rajadhammas in governing Kosala and Kasi. As the householder; he used Gharavasa-Dhamma , Samajividharma. In the body, King Pasendikasala used the Buddhist way to lose weight, that his body is uncomfortable. In the 16 things of King Pasendikosala’s dream, it could predict that the world is going to happen in the present. The King Pasendikasala have a beautiful activities and in particular benefactors to human life today.

For  conclusion, Upasaka and Upasika should study the roles and the activities in various fields of the King Pasendikosala in order to apply benefits and values for themselves, their families, organizations and nation. Especially, should study the Dharma teachings and propagate Buddhism to flourish forever.