Based on observation data and NWP products,some diagnosis fields for rain enhancement were worked out and the real-time automatic display on MICAPS platform was realized.The supersaturation with respect to ice can be used to diagnose the vertical distribution of ice-water conversion area,then determine the seeding height.The vertical disposition of T-T_d can show the altitude and depth of the quasi-saturation layer,the top of which was the suitable seeding position.The height of the characteristic temperature layer can be used to determine the altitude and thickness of "seeding temperature window," a seeding position criterion.The optimal seeding altitude can be determined by synthesizing above methods.The trend of rainfall enhancement potential coefficient was identical with that of rainfall,which can provide reference for choosing appropriate seeding time.The above-mentioned methods were applied during a typical rain case. In the weighted integrating manner,several environmental physical fields and rainfall forecast were synthesized,and the graded forecast of rain enhancement potential was made.The verification was conducted by seven stratiform-cloud rain cases occurred from February to May 2004.The results show that the method is encouraging.