Some Factor’s That Affecting The Mathematic Teacher Performance For Junior High School In Medan. This research will examine the effect of direct and indirect of the Organizational Knowledge towards the achievement motivation, decision making, organizational commitment, the performance of mathematics teacher. The research method is a method of surveying the number of respondents as many as 102 teachers of mathematics taken by stratified proportional random sampling. The research found there is a direct influence of organizational knowledge on achievement motivation, decision making, organizational commitment and the performance of math teacher respectively 16.3%, 13.1%, 12.2% and 4.54%. Achievement motivation, decision making, and organizational commitment have directly effects on the performance of mathematics teacher. The magnitude of changes in performance that can directly determine organizational knowledge, achievement motivation, decision-making and organizational commitment respectively are 10.24%, 12.32%, 3.42% and 2.92%. To teachers of mathematics, in order to improve the understanding of the knowledge of the organization, increase achievement motivation through desire superior achievement and improvement of organizational commitment. For heads and school inspectors, need to improve clinical supervision and foster good communication increases the openness and good cooperation with teachers of mathematics, and for the head of the city education field, is expected to give a briefing and training for teachers, race through the efforts competitions drafting paper development learning mathematics.