To resolve the problem of low locating rate in fault diagnosis of air borne radio equipment

the idea was proposed to using preceding fault information in the tests of batch equipments.By studying the failure rules of batch equipments

the fault probability under extreme-small-sample conditions was estimated using Bayesian theory.Four methods were adopted to direct fault detecting.The simulation results showed that the strategy of this paper could improve the rate of locating faults correctly in one time detecting progress and reduce the fault searching time

and can enhance the efficiency of fault diagnosis.