Micro electric vehicle has gained increasingly popularity among the public due to its compact size and reasonable price in China in recent years. Since design factors that influence the power of electric vehicle drive-motor like maximum speed, acceleration time and so on are not fixed but varies in certain scopes. Therefore, to optimize the process of matching drive-motor power, qualitatively and quantitatively studies should be done to determine the optimal parameter combination and improve the efficiency. In this paper, three basic operating conditions including ascending, acceleration and driving at top speed are considered in the matching process. And the Sobol’ method of global sensitivity analysis (GSA) is applied to evaluate the importance of design factors to the drive-motor’s power in each working mode. Then the most influential factors in determining the peak power are identified with Sobol’ method and an improved algorithm proposed in paper by regarding the design process as a black-box model, for the power of drive-motor must meet the three performance requirements of micro electric vehicle after all. Finally, local sensitivity analysis (LSA) based on the perturbation method is adopted to evaluate the impact of parameters variation on the power of drive-motor in a small range. In conclusion, the sensitivity analysis results reveal that acceleration time, transmission efficiency, vehicle’s maximum speed as well as the speed ratio of the drive-motor are the most crucial factors in the matching process while the others can be neglected under given conditions thus providing a reference to the enhancement of micro electric vehicle’s design efficiency.