The Order Assembly has been responsible for playing the role of the top legislative organ in the religious group that sees fair play in developing and operating it since it was organized when Order's Charter was announced on January 1970. The Order Assembly that has been held more than two times per year is located in Guinsa Temple, the headquarters. And it usually decides and passes projects and budget and settlement of the religious project through discussion.

The term in office of the members of the Order Assembly is 4 years and the fixed number of the assembly is 30 persons. The special thing is the fact that 1/3 of the members consists of believer members. It shows that four classes of the persons who follow Buddha's teachings and compose the Buddhists Priesthood participate in duties of the religious group as they are. Participation of the believers who cultivate themselves morally or religiously is not limited to the Order Assembly but is deeply involved in operation of small temples managed by the headquarters. The point that the believers who cultivate themselves morally or religiously participate in business of the religious group is Tiantai Buddhism's advantage that cannot be found in other religious groups of Buddhism.