Abstract: In order to use methanol as alternative automotive fuel, the basic 492QA automotive gasoline engine was retrofitted to 492M methanol automotive engine. Intake preheating is adopted to improve the mixture formation process and increase the intake temperature. The M90 fuel and PTC heater are used to improve the cold starting performance. And some important technical methods such as increasing compression ratio, selecting suitable spark plug, optimizing the spark timing are employed to improve the power performance and thermal efficiency. The maximum combustion pressure of 492M methanol engine is controlled designedly so as to assure the working reliability. The results from bench test 492M methanol automotive engine show that the power performance and thermal efficiency have been improved effectively, the maximum power, the maximum torque and the maximum effective thermal efficiency increases by 2.4%, 6.2% and 20.7%, respectively. And the maximum exhaust temperature decreases by 9.4%, which proves that the 492M SI methanol automotive engine has been successfully developed.