To achieve the laser accurately positioning on the target in high power laser facility, the error analysis method is necessary to actualize engineering of the facility and increase the technology of the correlational systems. The automatic alignment control system is mainly designed to establish and maintain laser chain alignment and eliminate the error, but the traditional error analysis method based on both contingency and system errors does not give a comprehensive analysis. So a new error analysis method based on both static and dynamic errors is developed. The optical system in the target area is analyzed with this method and a common equation of target positioning tolerance has been obtained. The satisfaction and feasibility of the error analysis are demostrated.