The screening out of cells specially abnormal cells by microscope is a very useful method for cytology diagnosing. Since inspecting pathological changes of cells by microscope is very slow, thereby study a new auto-microscope system with function of image processing is very necessary. This system has the following functions: 1) the microscope stage should be scanned in x and y directions, and a step distance of scanning is corresponded to a field of view of the microscope. 2) For autofocusing, first the micro-structure is low contrast, otherwise focus depth is very small. Therefore, autofocusing for biological microscope is different to common industrial microscope with low time and high contrast. 3) The microscope must possess image processing functions to recognize and screen out cells. 4) The system possesses function for auto-photograph. Because the field of view of the microscope is very small, if all fields of view are photographed one by one, then several hundred thousands or several millions fields of view will be photographed. But there is no target in most of fields of view, i. e. , only a few is useful, so, it is necessary to screen out and auto- photograph them automatically. On the other hand, transmissivity of different targets is different, so the exposure time must be adjusted automatically. Besides that, this kind of camera must hold sufficient film, i. e. a large cassette must be disigned. The micrscope system with these functions is a complex auto-controlling system.