Abstract: In order to make the Bayesian networks dealing with fuzzy and uncertain information, a new reliability analysis method of multi-state system based on fuzzy Bayesian networks is proposed. The fuzzy set theory is presented to Bayesian networks, and considering both the fuzziness of fault state and fault rate and the uncertainty of fault logical relationship between components, therefore the Bayesian networks are capable of handing the fuzzy information. The fault states of system and components are described by fuzzy numbers, fault rates are denoted by fuzzy subsets, and the relationship between components described as conditional probability table of Bayesian networks. At last, the method is applied in the reliability analysis of the hydraulic suspension system of hydraulic transporter, the results show that the proposed method is able to make full use of fuzzy information and uncertain information in reliability analysis and can improve the efficiency of reliability analysis.

Key words: Fuzzy Bayesian networks, Hydraulic system, Multi-state, Reliability analysis