Serious games combine game entertainment with original purpose in special fields(education, health, sport, military, public), Now, many serious games have been developing in this country, but main points on development factors in serious games have not been presented. In this paper, we analyze existing games which were developed for psychotherapy with essential factors of human-service game presented by Hy Resnick and Moshe Sherer, for developing serious games in psychotherapy field. And, we discuss development methods of psychotherapy game based on the analyzed factors. This paper shows theoretical bases in serious game for psychotherapy, provides guidelines for developers to produce a serious game in psychotherapy.