In order to improve the fuel economy of commercial vehicle automatic transmissions during neutral coasting，the fuel injection quality and economic influencing factors of the automatic transmission neutral slip control process are analyzed. The neutral slip control strategy is optimized based on the time-based moving average window method and verified by combining road test spectrum analysis. The results show that the fuel consumption mass is fixed when the vehicle enters and leaves the idle condition，and the total fuel consumption mass during neutral coasting is related to the number of times when it enters and exits neutral coasting control and the duration of a single coasting. Reducing the frequency of entering and exiting neutral coasting control，minimizing short duration neutral coasting，and retaining longer duration neutral coasting can improve vehicle fuel economy. For the road test，the optimized neutral sliding control strategy is adopted to reduce the gas consumption per 100 km from 31.950 kg to 31.728 kg，saving 0.222 kg in gas consumption per 100 km.