A wireless sensor network is composed by hundreds or thousands of small compact devices, called sensor nodes, equipped with sensors (e.g. acoustic, seismic or image), that are densely deployed in a large geographical area. One of the most effective sensor network types is critical sensor network. In such kind of network, some nodes are connected to environment called critical sensor nodes and some nodes are defined as normal sensor nodes. Complete system depends on the critical nodes. Because of this, it is required that the critical nodes are always in processing situation. To analyze whether these nodes are working or not it is required to monitor these nodes regularly. In this paper, an approach is defined to analyze these critical nodes.