The invention provides an IPv6 (internet protocol version 6)-based wireless sensor network structure and an intra-subnetwork switching method. The structure comprises a gateway node, fixed nodes, collaborative nodes and a mobile cluster, the mobile cluster further comprises moving nodes and a mobile cluster first node, the gateway node is used for managing and controlling communication of a sensor grid subnet with other subnets or other networks, the fixed nodes are common communication nodes and belong to full-function nodes, the collaborative nodes are used for relieving unevenness of power consumption distribution caused by network flow distribution unevenness and simultaneously used for reducing huge cost brought by communication among same-layer nodes, the mobile cluster first node is used for managing and coordinating the moving nodes and responsible for communication between the mobile cluster and the fixed nodes, a network node address of the network is a 128-digit IPv6 address, a complete 128-digit address is used for communication and addressing of the IP6V network, and 16-digit short addresses are used in intra-subnetwork switching and communication. The invention further discloses an intra-subnetwork switching method.