Abstract: The impact of utilizing 925hPa data on the analysis and forecast of height fields is analyzed detail in this paper by taking parrellel operational numerical experiments which last 15 days continually. The results show that,impact of adding 925hPa data into analysisa on height analysis is large, in north western Indian Ocean and the belt from malayzia to the tropical area south to Philippines, and is small, in other areas within the modael domain. Meanwhile, the impact on analysis of the general field is not very large as a whole, which is larger on lower level than on middle and upper levels. The errors result from vertical interpolations from the P-surface analysis field to the model o-surfaces can be remarkablly reduced as well. In addition, the impact on the 24 hour forecast fields is less than on the initial fields, while the stability for the model integration is raised and the results for forecast verification are obviously improved.