An image test system includes a test assembly and an image capture card. The test assembly is provided for obtaining a test signal from a test object, and includes an interface conversion circuit for converting signal transmission form of the test signal. The image capture card is provided for obtaining the test signal from the test assembly, and obtaining an image data from the test signal. The image test system further includes a test signal clock generation circuit for obtaining a test signal clock from the test signal, or the image capture card further includes a pair of clock input pins for obtaining the test signal clock directly from the test object.