The invention provides a certificateless signcryption method suitable for VANETs, and the method comprises the following steps: S1, obtaining vehicle-mounted network system parameters from a vehicle-mounted network system by employing a system building algorithm, and building a vehicle user IDi; adopting a false identity generation algorithm and a partial private key generation algorithm to generate a vehicle user false identity, the validity period of the false identity and a partial private key; generating a vehicle user secret value by adopting a vehicle user secret key generation algorithm; a vehicle user sender generating a user message, generating a signcryption ciphertext based on the partial private key, the user public key and the secret value, and sending the signcryption ciphertext to a vehicle user receiver; and decrypting the signcryption ciphertext through a verification equation to obtain a decrypted user message, and finally judging whether the decryption is valid or not. The method is an efficient and safe certificateless signcryption algorithm, confidentiality, authentication, integrity, non-repudiation and privacy protection can be provided for information transmitted between vehicle communication units, and safety guarantee is provided for vehicle-mounted self-organizing network safety communication.