Abstract: This paper introduces the design and realization of simple electronic organ based on SOPC and USB keyboard. Using the ML402 multi function interface board as the platform, a simple system on a programmable chip is achieved in the FPGA chip on the ML402. This system includes a CPU, data and instruction memories, and internal buses. On this basis, the USB interface and audio interface controller are added to the system. A USB keyboard is connected to a USB port as the keys of electronic organ, and the ML402 interface board is used as the USB host device. Through writing the CPU instruction codes in FPGA chip on the ML402, the USB keyboard value is read and keyboard notes are played.