Because of the low thrust，the time of planetary orbit insertion by electric propulsion has significantly increased.Electric propulsion has completely different characteristics from chemical propulsion，and greatly increases the difficulty in trajectory optimization.This paper focuses on the control problem of the low thrust trajectory of planetary orbit insertion phase，and takes the trajectory optimization problem of Mars orbit insertion as an example.Based on the hyperbolic orbit parameters，research is conducted on the switch and control strategies of planetary orbit insertion under different performance indicators.An indirect method is used to solve the energy-optimized plane trajectory optimization problem and obtain the optimal control strategy.The optimal control strategy is compared with the control strategy in the opposite direction along the velocity direction.The results indicate that the proposed method has achieved optimized design for low thrust Mars orbit insertion.The error in the captured orbit is smaller than that of the target orbit，and the orbital safety can be guaranteed.