Abstract: To realize a digital variable-speed system for SRM,a speed-controlling system of SRM based on DSP56F805 is presented.Control mode and control strategy are described,A 7.5 kW prototype with 8 stator poles and 6 practical rotator poles is developed.The prototype is put into practical performances in the laboratory as a control object.The results of the experiment show that the system is feasible and is provided with some good dynamic characteristics and steady precision.