A resistance spot weld controller was developed based on SEED-DEC2407 control board. The functional modules of the control board and its software integrated development environment were introduced. The total program frame of resistance spot weld controller was designed according to the requirements of resistance spot weld process, and the programming and debugging were performed respectively for the modules of UART, the timer, D/A and I/O. Finally, the total program of the controller was debugged and tested, and the results show that the developed resistance spot weld controller is practical.