This paper proposes a Q-Learning based trust management mechanism for clustered wireless sensor networks (QLTMM-CWSN) as a solution to the security problems in wireless sensor networks. This mechanism mainly considers three aspects: communication trust, data trust and energy trust. During network operation, the Q-Learning algorithm is used to update the node trust value based on the nodes’ communication behavior, nodes’ data distribution, and nodes’energy consumption. The node with the highest trust value in the cluster is selected as the trusted cluster head node. When the trust value of the main cluster head node in the cluster falls below the threshold, the trusted cluster head node replaces the main cluster head node to manage the member nodes in the cluster and maintain normal data transmission. The simulation results show that the proposed QLTMM-CWSN mechanism can effectively protect against communication attacks, forged local data attacks, energy attacks, and hybrid attacks.