The forming technique of micro-punching is an important method for precision plastic machining of micro-parts, the micro-hole size must be sub-millimeter in two-dimension. To punch less than 200µm micro-holes on thin plate and realize precise positioning, established positioning system based on micro-vision technology and detected the location of thin plate by the image of reference hole. Proposed a localization algorithm based on coordinate transformation, eliminated the positioning error, and achieved micro-hole positioning by controlling the servo platform. Completed the study on the image processing method, identified the reference hole by Hough and least-square circle detecting method.