Abstract: This paper puts forward a suited wireless sensor network node fault diagnosis algorithm to the characteristics of the underground wireless sensor network, according to the characteristics of the distribution of downhole sensor fault diagnosis algorithm for WSN node clustering DFD clustering way, cluster head node selection method, as well as improving on the stable ability after the clustering. Aimed at the specialties of the downhole application environment: the environment monitoring sensor is usually a long chain distribution within the roadway, cannot be carried out in accordance with the normal random distribution network structure. This algorithm meets the underground wireless sensor network node fault diagnosis algorithm for fault location accuracy, low energy and high stability. At the end, this paper compares beteween common algorithm and the improved algorithm by computer simulation and verifies the advantage of the improved algorithm: less energy consumption, high precision, thus have a stronger ability to survive.