Integrity probability is one of the evaluation indexes of civil aircraft and system safety. Cyclic Redundancy Check (CRC) is a widely used integrity design measure in avionics communication network. In view of the lack of quantitative safety analysis of CRC check, based on the performance of standard CRC check, the probability of undetected erroneous service data transmitting over avionics network was studied. Combined with cases, the influence of CRC check on the integrity requirements of avionics network transmission channel was analyzed. The analysis results show that the network transmission channel or the link layer may not need to consider integrity requirements for specific service data by adopting design measures such as CRC check at the application layer and ensuring that the probability of the service data being error and CRC undetected over the network meets integrity requirements allocated from top level, and thus mitigate the safety requirement of the network transmission channel. The analysis provides reference for CRC check design and safety analysis of avionics network.