Tang-Toennies potential model and close-coupling method were applied to the He-H2(D2,T2) system，and the vibrational and rotational excitation cross sections at different incidence energy have been calculated.By analyzing the differences of these partial wave cross sections, the change rules of the partial wave cross sections with increase of quantum number, and with change of reduced mass of symmetric isotopic substituted system have been obtained. Based on the calculation, influence on the cross sections exerted by the variations in the reduced mass of systems and in the relative incoming energy of incident atom is discussed.