Abstract: Wireless sensor network (WSN) is a resource-constrained network, especially, in terms of energy aspect. Hence, the goal of energy-efficiency should be achieved for WSN. For the reason that the WSN is application-oriented, the problem of energy consumption of WSN must be considered in an application-oriented way. It is necessary to get knowledge of the energy depletion of WSN in a real-time way. This requires that a reasonable model of energy consumption should be provided first. But the general assumption in the study of WSN energy consumption modeling is somehow not in accordance with the truth. For this reason, all the existing models of energy consumption are not available to real-world applications of WSN. To build up an application-oriented model of energy consumption, a comprehensive analysis of energy consumption is made, together with specific WSN applications. Specifically, the activities of wireless communication and computation, physical characteristics of WSN nodes, and the influence of all these factors on energy consumption are investigated. As a result, a model of energy consumption based on characteristic analysis of wireless communication and computation is proposed. Furthermore, a new energy consumption model is constructed practically, and the effectiveness of this model is validated. Finally, conclusion remarks are given.