The optical cameras, as the relative navigation sensor, are more and more applied in on-orbit servicing GNCS (Guidance, Navigation and Control System). Meanwhile, the GNCS capabilities in complex optical environments such as background light interference need to promote greatly. So we need to construct a test system in ground to test and verify the GNCS function and capabilities in on-orbit optical environments. But in present, the way of parallel tube and two-axes turntable cannot satisfy the need. This paper proposed a HWIL (hard-Ware-In-Loop) system based on dome-screen projector for on-orbit servicing GNC system. Based on this system, the optical environment of on-orbit camera can be simulated realistically, and HWIL test can be completed by testing fully the adaptability of GNCS in complex optical environments, and the sufficiency and comprehensive of ground test can be guaranteed.