To satisfy the request of communications equipment technical support of communications troops, put forward the faulty diagnostic methods based on Bayesian Network. After analysis the advantages of Bayesian network in the aspect of fault diagnosis of communication equipment, taking certain fault of certain communications equipment as an example, research these key technology, including: the modeling of Fault-diagnosis Bayesian Networks of communication equipment, parameter setting and reasoning, etc. This paper utilizes the software of NETICA to demonstrate the common process of diagnostic methods of fault based on Bayesian network, verifies the feasibility and validity of the applying Bayesian network in the faulty diagnostic methods of the communication equipment.