Abstract: Based on the fuzzy mathematics theory and reliability analysis, a fuzzy reliability-based optimal design method for the machine elements is proposed. Some main problems in the design method, including standard model, reliability analysis method, the determination of membership functions and the solution of the design model, are dealt with. A design example of gear transmission is given out. Theoretical model and example results show that the method has wide - ranging practical value and great spreading prospect.

Key words: Fuzzy mathematics, Machine design, Optimization method, Reliability theory