Abstract: About the convective weather in the summer of Beijing area, some researches have done before by using the conventional sounding data of 54511 station, the special sounding data constructed by microwave radiometer data as well as the wind profile data and the model output sounding data of the rapid updated cycle assimilation and forecast system for Beijing area (BJ-RUC). Now in this article, we discuss the experimental study of the convective weather probability forecast and the categorical (such as short-time convective rainstorm and the hailstorm) probability forecast in Beijing area based on the BJ-RUC meso-scaled model. On the model basic elements many different thermal and physical parameters are calculated and then some convective weather characteristic indicators are employed. In this study at least four experiments were compared and the best of them are used to analyze three typical convective weather events in the summer of 2009 and 2010 in the Beijing area. The experimental results show that the probability forecast of the summer convective weather can be achieved, and there are also some successes of the categorical probability forecast based on the BJ RUC in the Beijing area.