Abstract: To reveal the characteristic of convective activities in the Lushan area during the warm season and improve the refined forecasting and early warning capabilities for convective weather in this region, this study analyzes the spatiotemporal evolution, movement characteristics of convection during the warm season (April–September) in the Lushan area, as well as the impact of the coupling effect on convective evolution between Lushan Mountain and Poyang Lake. The Nanchang Doppler weather radar data from April to September during 2018–2022, combined with national meteorological station surface observation data, gridded lake surface air temperature products from the China Meteorological Administration Land Data Assimilation System (CLDAS) and the ERA5 reanalysis data were used, and a method based on the Barnes filter and Tracking Radar Echoes by Cross-correlation (BTREC) algorithm was adopted. The results showed that the frequency and intensity of convection over Lushan and its eastern side were significantly higher than those in adjacent regions at the same latitude. Seasonally, convection frequency was relatively high from May to July (peaking in July), while intensity was stronger from July to September (peaking in August), with July featuring both high frequency and considerable intensity. Diurnally, the high-incidence period was 12:00–16:00 (Beijing Time, the same hereinafter), during which convection intensity was optimal, whereas both frequency and intensity were weak at night. More than 80% of convection moved in a southwest–northeast direction, which moved faster with concentrated wind directions from April to June, and slower with increased wind direction dispersion from July to September. The coupling of Lushan Mountain and Poyang Lake affects convective activities through dynamic and thermal processes. Low-level lake wind invading the mountain forms low-level convergence zones to trigger and intensify local convection. The diurnal thermal contrast between the lake and land modulates lake-land and valley-mountain wind convergence, dominating the spatiotemporal distribution of convection with peak afternoon occurrence and concentrated activity over the lake–mountain junction. Based on these findings, 12:00–16:00 in the afternoon was identified as a key period for severe convection early warning in the Lushan area, and the southwest–northeast movement direction provided a core basis for predicting the impact range of convection.