The network of Integrated Modular Avionics (IMA) platform has complex communication structure. When fault injection testing, it is difficult to select a appropriate test path, and there are much equivalent and invalid fault injection. According to the characteristics of the network communication structure of the IMA platform, a new fault injection strategy was proposed. Firstly, according to the requirements of real-time and certainty in the network of IMA platform, a test path optimization algorithm based on communication links was proposed, optimal test paths were generated to achieve orderly coverage of IMA platform network test tasks. Secondly, after determining the test path, a test case automatic generation model was constructed by using Colored Petri Net (CPN) modeling method, the equivalent and invalid faults were eliminated, and test cases required for each test task in the path were streamlined. The simulation results show that the proposed method is less than the traditional fault injection strategy in terms of test times and test time, so it can overcome the shortcomings of disorder and blindness in the traditional strategy and reduce the time cost of the test.