Abstract:6LoWPAN enables the IPv6 communication over Wireless Sensor Networks, which defines two routing strategies: mesh-under if the layer concerned is adaptation layer and route-over if the network layer. To address problems in route-over forwarding for IP fragmented packets in 6LoWPAN, this paper proposes an improved route-over strategy based on virtual circuit which enables fragments forwarding in pipelined manner, and presents the design of the improved strategy which create a forwarding mapping for subsequent fragments based on IP compression header of the first fragment. The experiments show that the improved strategy proposed in this paper perform better than original one in transmission and time delay in dealing with IP fragmented packets.