The invention discloses a secure bidirectional heterogeneous digital signature method between a PKI and an IBC. System parameters are generated through a private key generation center, and the systemparameters are disclosed; the user in the public key infrastructure environment and the user based on the identity encryption environment generate a public key and a private key respectively; whereinthe user in the public key infrastructure environment is a signer, the user based on the identity encryption environment is a verifier, the signer generates a signature and sends the signature to theverifier, and the verifier verifies the signature, passes the verification and accepts the message, otherwise, refuses to accept the message; wherein the user based on identity encryption is a signer,the user in the public key infrastructure environment is a verifier, the signer generates a signature and sends the signature to the verifier, and the verifier verifies the signature, passes the verification and accepts the message, otherwise, refuses to accept the message. According to the invention, the safety, correctness, non-repudiation and unforgeability of communication between the publickey infrastructure and the user based on the identity encryption environment are protected, and the safety and privacy requirements are met.