The invention discloses a method for encryption authentication on an Ad hoc network transmission layer protocol, which comprises five parts and 18 steps, wherein the five parts are a configuration stage, an authentication stage, a key negotiation stage, an encryption process and a key update flow. The encryption authentication method of the invention is applied to a hand shaking process in the end-to-end communication between two nodes in a multihop Ad hoc network, wherein the two nodes pass through message authentication code verification (MAC) for mutual verification; after the authentication successes, key negotiation is performed by using an elliptic curve diffie-hellman (ECDH) algorithm; and a subsequent message is encrypted by using a shared key acquired in the key negotiation process as a key material and by using an advanced encryption standard (AES) algorithm, and a key update flow is initiated in a communication process. In the authentication and key negotiation process, an exclusive or gate (XOR) algorithm is used for encrypting authentication information and key negotiation information, the safety is high, the efficiency is high, the system expense is small, and the encryption strength is high; and thus, the method has a promising application prospect in the technical field of wireless networks.