This paper introduces a kind of method to design the numeral picture signal source,that is based on Camera Link protocol and FPGA.The picture data and interface signal are converted to low voltage differential signaling(LVDS) matching the Camera Link standard to transmit.This method can enhance the signal transfers distance,precision and offer the trustiness signal source to picture data acquisition system.It elaborates the design and circuit structure of picture signal source.In the end,it elaborates its actual application.This signal source has already been applied to a ground testing system.