Real-time response is essential for accurately getting path planning of optimal fuel consumption in rapidly changing traffic conditions. Based on the randomness and abruptness characteristics of traffic flow, this paper proposes an optimal fuel consumption path planning model in relation to routing nodes. Road impedance parameters routing tables of each node in transportation network are built and timely updated by sharing the traffic information from Internet of vehicle(IOV). Therefore, the path of optimal fuel consumption can be timely obtained by searching corresponding node's road impedance parameters routing table. In order to testify the fuel-saving effect of this proposed model, simulations are carried out in different traffic conditions to complete the same task and in the same traffic condition to complete different tasks respectively by altering traffic flow and destinations. The results show that the more congestion or the more transfer nodes, the better fuel-saving efficiency, so that economical and environment friendly travel can be realized.