This thesis aims to study the life and works of Ajarn Pratin Puangsumlee, ail important Thai dance teacher, in order to understand the forms and technigues she has used in creating her works of choreoghaply which reflect her unigue style. The study found that for more than forty years, from 1955 upto present Ajarn Pratin Puangsumlee her created a lot of works in Thai dances. The researcher can collect ninety five dances created by her which can be divided into seven catagories as follow : 1) dances to bless the king or ordinary people, 2) dances imitating arnimals’ characters, 3) dances for the Thai drama called “Phan - tang,” 4) miscellaneous dances, 5) dances based on religions and believes, 6) dances to be performed with music only (without lyrics) and 7) dances implying morality teaching Among these works, the researcher (has) selected three famous dances : 1) “Yudawan Dance’’, 2) “Khan-Khom-Som-Khanay Dance”, and 3) “Thui-Ka-Leng Dance”, as case studies. The research found that Ajarn Pratin’s creation of Choreography for a large mumber of Thai dances manifests the following five characteristics : 1) The application of her knowledge in choreography as learned from tire Dramatic Arts College, 2) the application of life experiences retated to choreography both in Thai and foreign cultures, 3) the adaptability of works to suit the abilitis of performers of vorious ages, 4) the ability in composing and selecting the contents of songs suitable for the teaching of morality, 5) the ability to adapt the works to the changing time and society. In conclusion, Ajarn Pratin Puangsumlee is one of the dance teachers and choreographers who play important roles in Thai dances whose works will remain examples and guidelines for the creation of Thai dances forever.