Abstract: Lookup table based commercial FPGA is a most popular ASIC scheme in fast system prototype design. In the paper,a new idea of controlling and managing complicated logic circuits by on chip microprogram is suggested, since XILINX FPGA is ROM based.The results in real application are satisfying. The paper describes the method of microprogramming and skill of addressing in FPGA, figures out the circuit template of a typical microprogram controller with FPGA, and summarizes the feature and limitation of its application.