Abstract: In order to increase the success rate of satellite in orbit mission execution and reduce the impact of manual operation errors, discussing on-board autonomous mission planning of solar synchronous near circular orbit satellite, a method was proposed for load mission planning according to the solar vector of the orbit system. Using solar vector of the orbit system, the method was designed to derive the relative position and angle change between the satellite and the sun, to calculate some key points such as the start and end time of the satellite load mission, and then to control single machine on the satellite for mission observation. The results show that this method can significantly reduce the number of needed instructions from ground during satellite executes the mission, and reduce the observation error resulted from injection time delay of the ground. The method proposed in this paper can provide engineering reference for related satellite autonomous mission planning, and provide theoretical reference for on orbit intelligent decision-making in the future.