In wireless communication, energy present very serious problem which could be easily affect the lifetime of all the network. The increasing of the wireless connected object lead to the appearance of a new notion which is the Internet of Thing. With the development of the size of the network the quantity of data become more important which request more quantity of energy to consume. The technology of the IEEE 802.15.4 present very powerfull solution for all application dedicated to low energy consumed which justify our choice for it to study. This paper investigate an approach used to postpone the fault energy of node in the network. So we get the energy consumed by every node then we detect the node with lack of power. After that we propose a specific manner to get the Beacon Order (BO) and the Superframe Order (SO) for this node in order to more maintain the little power lasted in its battery. We use in our work the topology of tree with the mode of beacon enabled for wireless sensor network (WSN).