Principal-part participation is a behavior with tendentiousness and devotion as well as a guiding ideology of all teaching strategies. It can be reflected in various teaching-organization forms, and the modern teaching can't be carried out without principal-part participation. Team-cooperation study is a purposeful choice by teachers in process of teaching. Where there is no principal-part participation, there is no team-cooperation study. Team-cooperation study is advantageous to the increase of students' learning motive. It also enhances the opportunities for students as a principal part to participate in classroom activities and is considered as an efficient method of fair participation. The principal-part participation can enhance the briskness and effectiveness in the cooperative study, and strengthen the contributive consciousness of members of team as well.