From the precipitation data of 27 national automatic weather stations and 635 regional weather stations in northern Gansu Province of China, combined with the conventional air, ground, and ECMWF reanalysis data, 104 cases of typical short-time heavy rainfall from May to September during 2016—2019 were selected. In this paper, mesoscale comprehensive analysis of environmental conditions for the occurrence and development of short-time heavy rainfall in northern Gansu Province was performed, and some characteristics and laws of short-time heavy rainfall in this region were revealed. The results show the following: (1) The short-time heavy rainfall in northern Gansu Province primarily occurs from June to August, and the intensity of short-time heavy rainfall is mostly 10-20 mm. (2) The typical characteristics of short-time heavy rainfall weather in northern Gansu Province can be divided into four flow types: subtropical high marginal type, low-pressure trough type, northwest airflow type, and high flow resistance type. (3) The relation and difference between different weather conditions, flow types, and physical parameters are discussed. The circulation characteristics and physical factors indexes and thresholds of various short-time heavy rainfall weather are summarized. (4) The surface convergence line (cold front) is the key system triggering severe convective weather in northern Gansu Province, and the analysis of the surface convergence line (cold front) is critical for short-time near rainfall forecast. (5) Low-level southerly jet (significant streamline) convergence at 110°E and 37°N is an important basis for judging whether short-time heavy rainfall can occur in northern Gansu Province. The prediction accuracy of short-time heavy rainfall in 2020 is 63.6%, indicating that the established short-time heavy rainfall forecast index has a strong capability, providing a new way to improve the short-time heavy rainfall forecast and early warning ability.