Provided are a method and device for acquiring a message certificate in a vehicle networking system. The method comprises: receiving, by a Background Control Center (BCC), a privilege certificate request instruction sent by an On-Board Unit (OBU); generating and sending, by the BCC, a write control instruction to the OBU, receiving, by the BCC, an application grant request instruction sent by the OBU, the application grant request instruction being used for applying for use of a privilege certificate already written in the OBU to the BCC; and determining, by the BCC, the valid time for the OBU to use a designated privilege certificate, generating an application control instruction according to the determined valid time, and sending the generated application control instruction to the OBU, the application control instruction being used for indicating that the OBU uses the designated privilege certificate within the valid time.