In order to find out the influences of glow plug temperature on the performance of methanol engine, the influences of glow plug temperature on the combustion and emission performance of M100 methanol engine under different load conditions were studied on a compression ignition methanol engine with engine speed unchanged. The results show that the peak value of cylinder pressure and heat release rate gradually increases with the increase of glow plug temperature, the combustion starting point moves forward, the pressure rise rate increases, the fuel consumption decreases, and the effective thermal efficiency increases. However, the improvement effects of glow plug temperature change on combustion and fuel consumption were different under different load conditions. The improvement effect reaches the optimal at 20% load and gradually decreases with the increase of load. In terms of emission characteristics, NMHC emission reduces and NO_x emission gradually increases with the increase of glow plug temperature. CO and Soot emissions show a downward trend at 20% and 50% load with the maximum reduction of 22.92% and 70% respectively, and slightly increases at 80% load; Unconventional emissions such as unburned methanol and formaldehyde show a downward trend with the maximum reduction of 47.64% and 32.87% respectively.