Aiming at the low recognition accuracy rate of micro image edge detection, a new edge detection method of micro image accessory based on processing matching was proposed. Analyze different micro images of micro accessories, picked up an edge transition zone, establish the math model for edge transition zone, confirm the edge point position based on math model. Establish the edge image fractal evaluation model based on microscope measurement, and analyze the similarity of same micro-machining model and test it by example. The test result shows