Abstract: In traditional probabilistic mechanism analysis, reliability analysis model of path generating mechanisms is set up with motion error of each coordinate.Because these kinds of mechanisms have multiple motion output components.The probability that a mechanism realizes its desired motion within a specified error is then calculated.In this work, each component of motion is taken as a failure mode and the kinematic reliability analysis model of path generating mechanisms is proposed with multiple failure modes in order to obtain the comprehensive effect of component errors.Based on statistical correlation analysis of failure events, the joint probability density function of each motion error is obtained by using two-dimensional normal distribution.The kinematic reliability is then calculated with the numerical integration method.The method is demonstrated by the analysis of a four-bar path generating mechanism.This model can provide a global failure of probability at a specified point during the motion interval.