Abstract: In order to analyze the effect of gear number on the energy consumption of electric bus and the gearbox configurations, a power-train model of an electric bus was build, the AMT gear number was configured to be 4,3 and 2 respectively. Dynamic programming was applied to find out the optimal gear shifting trajectory for the 3 gearbox configurations under 4 different driving cycles, then the two-parameter gear shifting strategies were extracted from the optimal results, and the minimum energy consumptions for the 3 gearbox configurations were achieved from simulation. The result shows that: compared to 4 speed gearbox, using 3 speed gearbox bring 1% extra energy consumption, while 2 speed gearbox bring about 5% extra energy consumption.