Wireless sensor networks use small nodes with constrained capabilities to sense, collect, and disseminate information in many types of applications. As sensor networks become wide-spread, security issues become a central concern. The design of key agreement protocols, whose main objective is to provide secure and reliable communication, is one of the most important aspects and basic research field of secure wireless sensor networks.Self-certified public key system, which does not require certification management and has no key escrow problem, is ideal for resource-constrained wireless sensor networks. However, the existing sensor network with key agreement protocols based on self-certified public cryptography is low security and great energy consumption. First of all, after the protocol proposed by Yoon et al is analyzed, it is pointed out that the protocol can not resist the key compromise impersonation attack. Then the idea of the implicit authentication in the MTI protocol families is adopted to devise a new authenticated key agreement protocol for wireless sensor networks using self-certified public key. To our knowledge, the proposed scheme is the first provably secure key agreement protocol for wireless sensor networks based on self-certified public key system. The scheme not only provides greater security, but is the most efficient communication and requires less energy compared with the existing relevant protocols, because of only two-pass message exchanges.