The unqualitative and nonlinear problems of virtual displacement in nonholonomic system are studied. The concepts of intrinsical linear nonholonomic constraint and intrinsical nonlinear nonholonomic constraint are put forward. The spectrums in applying all kinds of the virtualdisplacement concepts and the commutativity operations were testified and given. The study shows that,in intrinsical linear nonholonomic system, all kinds of the virtualdisplacement concepts and the commutativity operations are rational; But in intrinsical nonlinear nonholonomic system, they are not rational. So the physical realization of intrinsical nonlinear nonholonomic constraint must be studied.