Abstract: A perturbation approach to error modeling of robot linkage is presented in this paper,by which poseerror models of a robot linkage can be established through combining the small displacement vectors of allsource errors.The pose error due to various kinds of source errors,such as the clearances and the axesaberrations of joints,can be analysed withoat any differentiation which is required in other methods.Errormodels obtained from the perturbation approach are simple and their physical concept is obvions.For il-lustration,error modeling of a PUMA 560 robot linkage is made.