Aiming at the defects of FPC solder surface, a detection method based on image processing is proposed. Firstly, the average image of no defect FPC is obtained as a reference，and defect’s location can be achieved by image difference method. And then, information entropy is introduced to describe color fluctuation and geometrical morphology on FPC solder for quantifying and extracting texture feature. The color and area feature can also be used to discriminate non-defective and defective solder. So, all the defective solder can be detected according to color, area and texture characteristics. The performance of the proposed defect detection algorithm is finally evaluated on-line testing. The average detection time of 50 solders is 300ms, and the detection accuracy can reach up to 97.8%.It is very fit for real time detection.