Because there is not indoor test equipment for narrow field of view (FOV) star tracker, and outfield experiment and actual flight will involve a lot of efforts such as heavy financial budget and high difficulty. To debug the performance and test algorithms of the integrated navigation system, a hybrid simulation system of celestial navigation system/inertial navigation system/global navigation satellite system (CNS/INS/GNSS) integrated navigation system based narrow FOV star tracker was proposed. The system emulates the error simulation model based on the actual collected navigation source data, generates the simulation data, and then combines the navigation processor and the display control unit in the prototype of the integrated navigation system to form the hybrid simulation system. It has a feature of flexibility and extensibility and can be used to reduce effectively the experimental expense and shorten the developing period of integrated navigation system, which is significant for studying algorithm performance, system specialty and project application of integrated system.