Flatten precision is one of the important factors effecting on camera's resolution. It is required that the film in a aerial camera with long focus

wide frame and high resolution should be flattened on film board quickly and precisely during exposure time. Aiming at the film size of 114 mm × 114 mm

flatten precision of 0.034 mm and absorption time of 420 ms

this paper introduces a perfect film flatten system

and provides a method for flattening the film on the film board using negative pressure. The constitution and operating principle of this system are introduced

the structural style of film board is clarified and the choice basis of key devices are obtained by analyzing and computing.The results show that the proposed method is a excellent optical method used to analyze flatten precision

which can meet the demand for aerial frame film camera.