Abstract: The present invention saves space by having an image sensor testing system that includes an image capturing module, an image storage module, and a signal processing module that are integrated on a mainboard. The mainboard uses multiple wires to respectively electrically connect to the image capturing module, the image storage module, and the signal processing module, and the image storage module is electrically connected to the image capturing module and the signal processing module. The image capturing module captures an image signal generated by an image sensor, the image storage module stores the image signal, and the signal processing module processes the image signal into a processed image signal and analyzes the processed image signal to obtain an image test value. The image capturing module and the signal processing module both directly access the image storage module, allowing the image test value to be calculated with less processing time.