Abstract: Based on the strong deformation which has taken place in the Himalayas and the Tibetan plateau caued by the northward push of the Indian plate since Cenozoic, an estimate by simulation is made of the strain rate of each tectonic unit and the consequent amount of u-plifting and shortening of the Plateau since 40Ma B.P.using two-dimensional visco-elastic Finite Element Analytic Method.The Mechanical Paramaters of rocks of each terrane, espe-cially the order of magnitude of the effective viscous coefficient η are deduced by inversion method.Detail calculation shows that in addition to the dynamic mechanism and boundary condition, the physical property of rocks play an important sole in determining the tectonic stress field and strain rate.It is the varied mechanical properties of the different lithospheric layers that lead to the difference in the stress field, displacement field and in the strain rate and resulting comolication of geologic strctures.