As an ideal green vehicle, electric aircraft is expected to be widely used in the future. It is a very complicated process for an airplane to run from acceleration to flight to a safe altitude. When calculating the take-off performance of an electric aircraft, it is found that the take-off distance obtained by the approximately uniform acceleration simulation model is always smaller than the actual take-off distance. In order to accurately calculate the take-off performance of electric aircraft, a simulation model of the complete take-off process was established in MATLAB and the error between the model and the actual take-off process was analyzed. By analyzing the change law of acceleration and speed during the take-off process of electric aircraft, a modification function was introduced to modify the Speed in the model. Taking an electric aircraft takeoff performance calculation as an example, the model before and after the modification is used to simulate the takeoff process and compare the calculation results with the flight test data. The results show that the accuracy of the modified model is better than the simulation model before modification, and the simulation results of the revised model are basically consistent with the results of the aircraft flight test.