The purposes of this study were 1) to examine the conditions of student affairs administration, 2) to study the student affairs administrative process in the successful school, and 3) to create the student affairs administrative strategies of Secondary School in Thailand : A case study of Nonsungsritani school under secondary educational service area office 31. There were 4 strategies on the student affairs administration namely: 1) Creativity student care and support system 2) Empirical moral ethics promotion 3) White school without drug problems 4) United promotion on democracy in school.