Fousing on the necessary of avoiding the detection of missile by enemy satellites,a calculation method of satellite coverage in space area was firstly discussed. Then, the evaluation index of missile trajectory safety was put forward, and the optimization model of missile trajectory safety path planning was constructed. Based on the analysis of space coverage, a missile flight planning and decision support software system with completely independent intellectual property rights was designed and developed. The architecture and function modules of the software were deeply analyzed.The simulation result proves that the system can make the missile in the monitoring range of introsystem satellite and avoid the detection of enemy satellites, which improve the probability of successful penetration.