Abstract-The security of hierarchical wireless sensor network (HWSN) attracts more attentions with the rapid deployment of HWSN recently. In this paper, the user authentication technology of HWSN is investigated and a more efficient and more secure user authentication protocol is proposed. Overcoming the main faults of the previous protocols, this enhanced protocol makes the improvements in achieving the strong anonymity, preventing the attackers of guessing the password of the lost smart card, and updating the secret information independently and quickly. The security of the protocol is verified by using the Rubin Logic method. The computation load is evaluated and is acceptable for the real systems.