To solve the satellite observation planning problem for emergency tasks with timing limits, the process of satellite observation is analyzed, and a whole cycle mission planning model on satellite observation is proposed. The model integrates four phases of satellite observation, to satisfy the timing limits of satellite observation missions in emergency. A heuristic algorithm was suggested to solve the model, and an optimization adjustment strategy based on conflict queue was also proposed. Simulation results show that the model and algorithm are feasible for mission planning of satellite observation, and improving the mission accomplishment ratio of independent mission planning for each phase.