Abstract: In the research and development of electronic speed governor for the emergency diesel generator, its function must be verified by simulation so as to save the development time and avoid major technical problems in the phase of coordination between prototype governor and diesel engine. Based on the domestic mainly used diesel generator 12PC2-6B in nuclear power plant as the target model, the diesel generator simulation model was developed. The diesel engine model includes cylinders, inlet and exhaust valves and pipes, turbocharger,crankshaft and other core components, which can reflect the transient performance of diesel engine comprehensively and accurately. Based on the actual control algorithm of the prototype governor, the simulation model of the electronic speed governor was developed. Before the engine matching test, the simulation models of electronic speed governor and diesel engine were combined to simulate the speed response in starting, loading, unloading, overspeed protection progress, so as to verify the control algorithm of electronic speed governor.