Abstract: With the rapid development of automotive electronics, network and information technology, the information security problem facing the Internet of Vehicles is also becoming more and more serious. Based on the transport layer link hijacking attack principle, a data transmission protection method based on encryption algorithm is analyzed and designed. By analyzing the three encryption algorithms of DES, 3DES and AES, the feasibility analysis is carried out from two aspects of security and implementation. The AES algorithm is selected to encrypt the data of the car network transmission layer. Experiments show that this method can effectively improve the security of car network data transmission.