The classroom action research as always been one of the most important learning process issues at school. Due to this importance, a research to improve activities and student learning outcomes needs to be done. This paper is focus on how to improve activities and student learning outcomes through Cooperative Teaching Type A (Divisions of Achievement) STAD Class X SMA PKP DKI Jakarta. This research will be devided into three cycles to analyze classroom action research. In the first cycle, student activity are increased reached the average of 57, the second cycle average 66 and the third cycle average 85. In the first cycle, teacher activity in learning process is also increased reached the average of 75, the second cycle average 82 and the third cycle average 86. In the first cycle, the competence of students are increases by implementing Cooperative Teaching STAD reached the average of 67, the second cycle average 70 and the third cycle average 81. It can be concluded that the application of STAD cooperative teaching can increase the students and teachers activity of learning process and can create the atmosphere of learning more comfortable and fun.