In order to reducing calculate costs of Bayesian network, when calculating posterior probability of samples that
need the marginal distribution, an approach of Bayesian network classifier based on conjugate prior distribution is proposed.
An adaptive discretization method is also proposed to discrete non-interval samples. The fault feature of analog circuit
extracted by wavelet packet is taken as a discrete property of Bayesian network classification model. The simulation result
shows that, this classifier has high accuracy and efficiency of analog circuit fault diagnosis, and can be applied to continuous
and multi-classification case, which extends the scope of application of Bayesian network classification.