Abstract: A key problem in dynamic wireless sensor network is the effect of moving nodes on the change of network connections. Analyzing the influencing factors on the change of the connections on the link layer of mobile wireless sensor networks, i. e., the node moving speed and network load ratio, the node moving speed in network is described efficiently with the concept of speed radius ratio so as to investigate the joint effect of the two influencing factors. Based on the in-depth study on the change of link layer connections in network and lots of data resulting from simulative tests, a conclusion is drawn that the connection changing rate increases with increasing speed radius ratio but decreases with increasing network load ratio. The conclusion provides a valuable reference for the applications in wireless sensor networks and the study on upper layer protocols.