Abstract: The short-time heavy precipitation processes over Yunnan Province caused by the shear lines during 2015–2019 are obtained, based on the precipitation data from the 125 national automatic weather stations and 3042 regional automatic weather stations over Yunnan Province, the FY-2E/G satellite imagery data, and the radiosonde observation. Furthermore, the following four aspects are explored: the characteristics of the temporal and spatial distributions of the short-time heavy precipitation processes, the mesoscale convective systems(MCS), the backgrounds for the occurrence and development of MCS, and the evolution of the convective clouds. The results show that there are four centers for the frequency of the short-time heavy precipitation caused by the shear lines over Yunnan Province, which are the southern edge of Yunnan Province, the regions from southern Qujing to northern Wenshan Prefecture, Huaping County of Lijiang Prefecture, and western Dehong Prefecture. Besides, the short-time heavy precipitation mainly occurs between evening and early morning. The convective clouds related to the short-time heavy precipitation caused by the shear lines over Yunnan Province can be divided into four types: newborn convective cloud clusters, M_αCS, M_βCS, and banded MCS, among which, M_αCS and M_βCS result in 75% of the short-time heavy precipitation processes. In M_αCS and M_βCS, the cold cloud with temperature below –32 ℃ is elliptical and they cover respectively 18,000 km² and 104,000 km². Besides, one or two centers exist in the elliptical cold cloud, and the central cloud top brightness temperature is lower than –52 ℃. Averagely, the duration of M_αCS is 3.3 hours, with the longest lasting for 6 hours. Meanwhile, the average duration of M_βCS is 2.3 hours, with the longest lasting for 5 hours. Short-term heavy precipitation occurs either around M_αCS and M_βCS centers or in the gradient maximum valued regions in the development direction. The coupling between low-level and upper-level circulation systems, the conditions for the occurrence of the convections, the occurrence and extinction of the MCS, and the characteristics of precipitation are comprehensively analyzed so as to establish the conceptual models for four kinds of the short-time heavy precipitation processes caused by the shear lines, which also provides the key technologies for the forecast of the short-time heavy precipitation in Yunnan Province.