A key management and node authentication method for a sensor network is disclosed. The method comprises the following steps of: 1) keys pre-distribution: before deploying the network, communication keys for establishing security connection between nodes are pre-distributed to all of nodes by a deployment server. 2) Keys establishment: after deploying the network, a pair key for the security connection is established between nodes, which includes the following steps of: 2.1) establishment of shared keys: the pair key is established between neighbor nodes in which the shared keys are existed; 2.2) path keys establishment: the pair key is established between the nodes in which there is no shared keys but there is a multi-hop security connection. 3) Node identity (ID) authentication: before formally communicating between nodes, the identity is authenticated so as to determine the legality and the validity of the identity of the other. It is possible for effectively resisting attacks such as wiretapping, tampering, and replaying and the like for the network communication, realizing the secret communication between the nodes, effectively saving resources of the nodes of the sensor network, and prolonging the service lift of the sensor network in the method.