Abstract: The paper proposes a seamless mobility handover scheme, SMH, for 6LoWPAN wireless sensor networks. In SMH, the control information for mobility handover is interacted within one hop scope, and the routing of the control information is automatically performed through the IPv6-ingress-node-tree network architecture, which reduces the mobility handover cost and shortens the mobility handover delay. SMH proposes the hierarchical structure of the IPv6 address for sensor nodes and effectively shortens the length of an IPv6 address, which reduces the transmission cost. In SMH, a mobile sensor node does not need a care-of address during the mobility handover process, that is, SMH does not need to perform the binding operation between a mobile sensor node's home address and its care-of address, so the mobility handover cost is reduced and the mobility handover delay is shortened. From both the theoretical perspective and the simulative perspective, the paper analyzes the performance parameters of MIPv6, Inter-Mario and SMH, including the mobility handover cost and the mobility handover delay. The analytical results show that the mobility handover cost of SMH is less and the mobility handover delay is shorter.