Abstract: Wireless sensor networks have some obvious characteristics, such as communication range is limited, energy-constraint, network is vulnerable et al. Group key agreement in this environment requires a cross-cluster, and computation and communication overhead are lightweight and highly safe group key agreement protocol. Aiming at these demands, the paper proposes a cross-domain lightweight asymmetric group key agreement, in order to establish a safe and efficient group communication channel among sensor nodes. Firstly, the protocol establishes the secret information among the cluster heads, and the cluster head as the bridge node to realize the sensor nodes in different cluster have the same group key information, thus realizing the cross cluster asymmetric group key agreement. The whole network node can share the secret information with the internal nodes of the group, which realizes the group security communication mechanism of the message sender unconstraint; proposed an asymmetric calculation to achieve computation and communication migration technologies to ensure that the sensor nodes are lightweight computing and communication consumption. For our asymmetric GKA protocol, the key confirmation is simple and requires no additional rounds if the protocol has been correctly executed. Proven and analysis show that the proposed protocol has the advantages in security and energy consumption.