A method for processing pseudonym certificate of an on-board apparatus, wherein the method is applied to the on-board apparatus based on vehicles to everything, the method including: generating a secret key and storing the secret key into a security storage unit of the on-board apparatus, wherein the security storage unit is only used to store data corresponding to pseudonym certificates; transmitting a pseudonym certificate request, which is generated based on the secret key; acquiring a first pseudonym certificate corresponding to the pseudonym certificate request, and generating a pseudonym certificate private key based on the first pseudonym certificate and the secret key stored in the security storage unit; wherein generating a pseudonym certificate private key based on the first pseudonym certificate and the secret key stored in the security storage unit comprises: determining (S103a) a time period of the pseudonym certificates and the number of pseudonym certificates within the time period based on the first pseudonym certificate; determining (S103b) a public key cocoon based on the time period and the number of pseudonymous certificates within the time period; determining (S103c) an expansion private key based on the public key cocoon; processing (S103d) the first pseudonym certificate based on the expansion private key to obtain a first pseudonym certificate private key, characterized in that the public key cocoon is determined directly by the on-board apparatus. generating a secret key and storing the secret key into a security storage unit of the on-board apparatus, wherein the security storage unit is only used to store data corresponding to pseudonym certificates; transmitting a pseudonym certificate request, which is generated based on the secret key; acquiring a first pseudonym certificate corresponding to the pseudonym certificate request, and generating a pseudonym certificate private key based on the first pseudonym certificate and the secret key stored in the security storage unit; wherein generating a pseudonym certificate private key based on the first pseudonym certificate and the secret key stored in the security storage unit comprises: determining (S103a) a time period of the pseudonym certificates and the number of pseudonym certificates within the time period based on the first pseudonym certificate; determining (S103b) a public key cocoon based on the time period and the number of pseudonymous certificates within the time period; determining (S103c) an expansion private key based on the public key cocoon; processing (S103d) the first pseudonym certificate based on the expansion private key to obtain a first pseudonym certificate private key, characterized in that the public key cocoon is determined directly by the on-board apparatus. determining (S103a) a time period of the pseudonym certificates and the number of pseudonym certificates within the time period based on the first pseudonym certificate; determining (S103b) a public key cocoon based on the time period and the number of pseudonymous certificates within the time period; determining (S103c) an expansion private key based on the public key cocoon; processing (S103d) the first pseudonym certificate based on the expansion private key to obtain a first pseudonym certificate private key, characterized in that the public key cocoon is determined directly by the on-board apparatus.