Abstract Based on FY-2G geostationary meteorological satellite and precipitation data, the spatiotemporal distribution characteristics and their relationship of convective clouds and heavy rainfall in mountainous areas of southwestern Sichuan were analyzed under the influence of the western Sichuan Plateau at the eastern side of the Qinghai-Tibetan Plateau from June to September during 2019-2021. The results show that: (1) The Ganzi Prefecture (98～103°E, 28～32°N) of the western Sichuan Plateau in the southeast part of the Qinghai-Tibetan Plateau is an active center of convection, and convective clouds mainly move southwards following the northwest path from the western Sichuan Plateau. After arriving at the Panxi region of mountainous areas of southwestern Sichuan, convective clouds keep moving in three directions: eastward, southeastward, and southward, respectively. And these pathways areas are also the key formation areas of heavy precipitation in mountainous areas of southwestern Sichuan. (2) Heavy rainfall related to the northwest path influence in mountainous areas of southwestern Sichuan is more significant in June-July than in August-September, with the most in July and the least in September. Moreover, the frequency of heavy precipitation for the southeastward-moving type is the highest, followed by the southward-moving type, and the eastward-moving type is the least, exhibiting prominent inter-monthly variation. (3) In the key area of the western Sichuan Plateau, because of the typical north-south ridges of Hengduan Mountains, the Shaluli Mountains and Great Snow Mountains form the generation area of the initial convection for heavy precipitation under the northwest path influence at 14:00~15:00 Beijing time, while the characteristics of their initial convection, the influencing time and the precipitation peak differ from each other for the eastward-, southward- and southeastward-moving convections. (4) The hourly short-duration heavy precipitation under the northwest path influence has obvious characteristics such as single peak and night rain, while the abruptness, duration and intensity of heavy precipitation for the eastward-, southeastward-, and southward-moving convections exhibit certain differences. (5) Although the initial convection and the convective clouds that first affect heavy precipitation along the northwest path in mountainous areas of southwestern Sichuan both originate from the key area of the western Sichuan Plateau, these features such as the convective location, development impact, precipitation distribution and precipitation center are disparate depending to the next eastward-, southeastward-, and southward-moving types. In a word, it is of important significance for further understanding the meso- and micro-scale convective activities and its influence on heavy precipitation in complex mountainous areas under the topography of the Qinghai-Tibetan Plateau.