This paper proposed a protocol for zero-knowledge proof of identity based on ElGamal on conic. It is more appropriate than the traditional identity protocol in distributed environment without trusted third parties. The security of this protocol relies on the discrete logarithm problem on conic over finite fields. Compared with those identification protocols implemented on elliptic curve, this protocol can be designed and implemented easier. And compared with that security lies on disassemble a large number, it runs faster. Corresponding to the simple version, a parallel version is presented subsequently. The characteristic of ZKp and security of the simple version is proved. The "soundness", "completeness", and amount of computation are also analyzed. A simple solution considering ttimeout is proposed to prevent a potential leak of our protocol.