分析了磁控法测量电子荷质比实验中电子的动力学方程，给出了磁控法测量电子荷质比的理论计算公式；并利用动力学方程模拟计算了电子的运动轨迹，计算表明：在阴极半径不为零的情况下，电子运动呈现为旋转的多个心形线的交错曲线这一类周期运动．利用模拟计算，验证了我们所得到的理论公式与动力学方程模拟的实验结果基本一致，从而验证了所给出的理论公式是正确的，且具有普适性．

The dynamic equation of electron in the experiment of measuring charge-mass ratio of electron by magnetic control method is analyzed, and the theoretical calculation formula of measuring the charge-mass ratio of electron by magnetic control method is given. The electron trajectories are further simulated by using the dynamic equation. The calculation results show that under the condition of non-zero cathode radius, electron motion exhibits a kind of periodic motion such as alternating curve of many rotating heart-shaped lines. By means of simulation calculation, it is verified that the theoretical formula obtained by us is basically consistent with the experimental results of dynamic equation simulation, thus verifying that the theoretical formula given is correct and universal.