Aiming at the problems existing in point-to-point communication model of Wireless Local Area Network (WLAN) protocol via Near Field Communication (NFC) authentication, such as plaintext transferring, user's anonymous access, data being easily tapped and tampered, a security design of WLAN protocol via NFC was put forward. The security tunnel was built using Diffie-Hellman key exchange algorithm and second generation Secure Hash Algorithm (SHA) to transfer the random information, and the user's anonymity was eliminated using Elliptic Curve Digital Signature Algorithm (ECDSA). A prototype implementation on computer was given from requirement analysis, architecture design and sequence steps of the protocol. The experimental results by using Colored Petri Net (CPN) modeling show that the proposed protocol can execute stably and deal with the unauthorized access and eavesdropping problems of WLAN.