The uncertain parameters of vehicle semiaxle were described by interval numbers,combining interval analysis with reliability design method,a non-probabilistic reliability model of vehicle semiaxle was presented.It discussed a measurement method of reliability with non-linear function for multiple interval variables.Based on interval analysis,a non-probabilistic reliability design idea for vehicle semiaxle was proposed.Finally,on condition that distribution function of parameters was unknown and interval numbers were known,an example of reliability design of vehicle parts was given,a maximum response stress was obtained.The research shows that the approach is reasonable,and the initialization is brief required.The most important is that it can be applied to other parts of the reliability design.