Aiming at the problems of low observation efficiency and insufficient fuel in current space-based space observation tasks， this paper proposes a close orbit design method for space multi-target skimming observation based on particle swarm optimization algorithm and space multi-target observation model to achieve the close range skimming observation of specific multi-target under the condition of constant orbit. The space multi-target observation model is established by combining the distance calculation of two orbiting satellites with the conditions of sky light and earth shadow. The particle swarm optimization algorithm is used to optimize the number of six orbits of the observer to obtain the optimal orbit for the comprehensive closest distance observation of a specific multi-target. The periodic difference generated by the orbital height difference is used to offset the phase difference between the target and the position at the intersection in a way that consumes time to get the most fuel-efficient way， and the formula for the most fuel saving is obtained at the cost of time. Finally， the numerical method is used to illustrate the effectiveness of the orbit design method.