This article introduces a micro-fluid Ink-Jet Printing Patch Method. By the printing method, we produce the micro devices like PLEDS, Color Filters, Bio Chips, et al. We then use the image understanding techniques to identify defect types, and perform the calculation of the optimum path to make the printing process stay at the most stable status, so that the patching micro device defects can be carried out and the yield rate can be improved.