With features such as the high data transfer rate of 1G/bps and strong compatibility, in-vehicle Ethernet can become the backbone network of next-generation in-vehicle bus network systems. Currently, in-vehicle Ethernet is mainly used in audio and video entertainment systems, to further improve the network security performance of in-vehicle Ethernet, the information security of the data layer and physical layer in the in-vehicle bus network system must be ensured. Based on the characteristics of in-vehicle Ethernet data frame structure, this paper introduces IEEE 802.1 Qci protocol, proposes an information fault detection method through data shifting, detection, and policing, and verifies it by simulation with OMNET++ simulation system. The experimental results show that the accuracy rate of in-vehicle Ethernet data during transmission can reach 99.61%, which further improves the network security performance of in-vehicle Ethernet.