A chain-type wireless sensor network(CWSN)for accessorial gas monitoring was established based on the geography features of a coal mine laneway.Fault modes of the coal mine gas sensors were analyzed.A gas sensor diagnosis method using CWSN and its algorithm was presented.The effects of different parameters(the gas distribution variance,thersholds and sampling frequency)on the performance of the algorithm were studid by using the Monte-Carlo simulation.The results show that,under appropriate threshold conditions,the performance of the fault diagnosis system is directly proportional to the sampling frequency and inversely proportional to the gas distribution variance.