Abstract: Atomic oxygen is one of the most important space environment factors in LEO space and can cause damages of surface materials and components of spacecraft, such as solar array, because of its serious erosion effect. The results of calculation and analysis indicate that the atomic oxygen fluence on the solar-directional solar array surface of LEO spacecraft is approximately one third of that on the ram surface. Atomic oxygen may have damaging effects on the materials of solar array to induce hazards such as the decrease of the blanket strength and electrical connection reliability, as well as the invalidation of the cable cover. Furthermore, the damage of the materials could result in the electrical performance degradation of solar arrays. It is suggested that the atomic oxygen fluence should be considered in the solar array design for the long-duration LEO spacecrafts to shorten the development cycle and reduce the cost. The solar array used in LEO should be exposed to atomic oxygen and tested for its electrical performance, because it is the best way to ensure the design reliability of the solar array for a long term LEO mission.