With the discovery of abundant gas hydrate storage, the natural gas will become an important fuel for future vehicles. In order to improve the starting performance of the CNG engine, an electrical control system was developed and the starting control mode was set up according to the engine operating characteristics. The control parameters of injection quantity, injection timing, ignition energy and ignition timing were considered in the model. The tests of start and idle were conducted on a four stroke CNG engine. The results indicated that the CNG engine can start faster and more reliably by using the optimal start control strategy.