This study analyzes the frontogenesis characteristics of rainstorms during the Meiyu period in 2020 using ERA5 reanalysis data and the precipitation data from automatic stations in Jiangsu Province.The main results are as follows:1) The characteristics of frontogenesis during the Meiyu period in 2020 are significant.Heavy rain is associated with middle-low frontogenesis,with deformation frontogenesis being the main contributor.2) Heavy rainfall during the Meiyu period can be categorized into two types.Severe convective rainstorms exhibit a larger frontogenesis range,higher development,greater intensity,and more overlap between total frontogenesis and decomposition terms.However,stable rainfall shows opposite characteristics.3) Two typical cases,namely the strong convective rainfall event on “6.28” and the stable rainfall event on “7.11” are selected.Frontogenesis occurs along shear lines and in regions of significant pseudo-equivalent potential temperature gradient.Strong convective rainfall is observed near the main frontal zone and in high-energy zones of pseudo-equivalent potential temperature,indicating the presence of multiple secondary frontogenesis centers.Stable heavy precipitation,on the other hand,is concentrated near the main frontal zone.These different rainfall distributions arise from variations in triggering mechanism and precipitation properties.4) The vertical front zone in both processes tilts northward from low to high.In the “6.28” process,a notable transport of warm and moist airflow is observed on the south side of the frontal zone,with strong upward motion within the frontal zone.In contrast,the “7.11” process exhibits less pronounced features and weaker convection.The magnitude and impact of frontogenesis differ across various precipitation processes and stages.Rainstorms are primarily generated by divergence and deformation frontogenesis,while the tilting term frontolysis in convective precipitation and frontogenesis in stable precipitation.Quantitative analysis of each decomposition term reveals that low-level divergence and deformation frontogenesis initially increase and then decrease in both processes.Deformation and divergence frontogenesis below 700 hPa are the main contributors,while the middle-high atmosphere experiences frontolysis.