CameraLink technology is a high-speed serial data connection standard widely applied in industrial cameras. In order to realize the displaying and processing of video based on industrial cameras with CameraLink interface, this paper has presented a video protocol conversion system based on Altera’s Cyclone Ⅲ FPGA. The system is able to convert CameraLink video outputted from the camera into High Definition Multimedia Interface (HDMI) signals for displaying. The system consists of power module, CameraLink receiver module, FPGA, as well as HDMI output module. The PCB of the system is designed with Altium Designer 16 and the software is designed on the Quartus II platform using Verilog HDL. The FPGA accomplishes CameraLink signal processing, color space conversion from RGB to YCbCr 4:2:2 and HDMI output chip configuration. The experiment results show that this system is stable enough that can reliably achieve HDMI video displaying, which is able to be applied to video displaying of industrial cameras with CameraLink interface.