Electronic endoscope is an important equipment in the modern medical instruments. With the increase of production, automatic welding of endoscope signal line has become an inevitable trend. A field programmable gate array (FPGA) image processing system for welding spot detection of endoscope lens module was designed to accurately and efficiently capture the welding spot coordinates of endoscope lens module. In the whole system, OV5640 is used as the image acquisition device to collect the image data of the target board. Image processing is carried out by Verilog HDL hardware description language for welding spot detection and defect discrimination algorithm. The hardware test results show that the system can collect the coordinates of solder joints in real time and detect the defects between solder joints. The maximum error of the collected coordinates is less than 0.1mm. the detection accuracy is high, and the real-time performance is high. The system has a wide application prospect.