In order to ensure that the extreme ultraviolet camera can point the earth exactly, monitor and research 30.4 nm radiation generated by the earth plasmasphere roundly and chronically, the control system of pointing mechanism was designed and developed. Firstly, the structure and the operating principle of control system were introduced. Secondly, the key modules of control system were designed in detail. Then, a control algorithm based on Hall sensor positioning was presented. Finally, the error sources of control system were analyzed in detail. The results of calculated errors and the work on lunar indicate that the control algorithm based on Hall sensor positioning is correct and effective, the control error of pointing mechanism is no larger than 0.1° and satisfies the requirement of extreme ultraviolet camera technical indexes.