There exists inevitably correlative multi-failure modes in a mechanism motion process; in most cases

they were described as random error functions. In order to analyze effectively these influences of correlative multi-failure modes on mechanism motion

a motion reliability calculation model was built by taking these multi-failure modes into account

and then the mechanism reliability results could be solved by this model. Taking type 6408 ball bearing as an example

the motion reliability value was 95.9989% after 100000 times sampling calculations. It showed that this method has high accuracy and is helpful to the theroretical research and practical applications.