Abstract: The density-constrained low-energy adaptive clustering hierarchy protocol, i.e., DC-LEACH, is proposed to meet the QoS requirement and minimize the energy consumption. Selecting the nodes in proper position as the clustering heads, the routing protocol reduces the energy consumption and alleviates the adverse effect on the communication quality, both resulting from the nonuniform distribution of nodes in network. In the protocol the probability analysis is made to fix the optimum measuring range in which the clustering heads are selected according to the threshold value of node density, thus giving the routing protocol of the network in clustering form. The simulation results showed that the improved protocol is able to not only reduce the energy consumption but also guarantee the communication quality.