Recent experiment have shown the size effect of the materials, when the characteristic length associated with non-uiform plastic deformation is on the scale of micros.The classic plasticity theories can't explain such phenomenon as their constitutive models posses no intrinsic length scale. The new models which contain strain gradient plasticity now are used to explain the experiment. Recently there are also crystal plasticity model to explain and predict the size effect of FCC and BCC.By this time, there have been many models such as CS, SG, MSG ,CMSG.In crystal plasticity ,there have benn models raised by A.Arsenlis, Evers, A.Ma, Gurtin, Yefimov...