The study selected 11 cases of severe convective weather processes in the weakly forced systems in East China from March to August in 2016 According to the main influencing system and different convective types, the study contrasts GRAPESMeso simulation with WRF simulation and observation data in terms of the atmosphere circulation situation, time and space of shorttime strong rainfall, as well as moisture, heat, dynamic condition, and thunderstorm wind conditions. Results show that in the lowerlevel weak convergence weather, the south wind near the shear line simulated with GRAPESMeso is weaker than the observation; the simulated accumulative precipitation becomes stronger in the second half of simulation; the simulated extreme hourly precipitation lags behind the observation. While for the convective weather under the subtropical anticyclone, the simulated accumulative precipitation can be divided into two types: one is similar to the observation, the other is clearly weaker. For the severe convective weather occurred among the two high pressure systems, the simulated precipitation is weaker than the observation. The GRAPESMeso simulated environment is warmer and wetter before the thunderstorm winds occur, and the simulated 0-3 km and 0-6 km vertical wind shears are mostly weaker than the observation.