利用常规观测资料、FY4A卫星、多普勒天气雷达及再分析等资料，对2018年7月19日内蒙古河套地区大暴雨过程的环流背景、环境场条件和中尺度对流系统（MCS）的演变特征进行了分析。结果表明：（1） 副热带高压稳定少动、500 hPa高空槽、低层切变线及西南急流、300 hPa高空急流和地面低压的配合为本次对流暴雨过程提供了有利的环流背景。（2） 低层持久的西南急流提供充足水汽输送，假相当位温高能舌、深厚暖云层、较高强度的对流有效位能、高空槽后冷平流入侵和上干下湿的不稳定气层为强对流暴雨的产生提供了较好的环境条件。（3） 东西向和南北向先后生成的MCS共同导致大暴雨过程的发生，对流暴雨主要是由于东西向MCS沿阴山山脉缓慢移动产生，20 mm·h^-1的强降水出现在上风向云团边缘及云顶亮温（TBB）梯度大值区附近。（4） 东西向带状回波移动速度缓慢且移动方向与回波长轴方向基本平行，强回波自西向东缓慢移动形成显著的“列车效应”，造成了5 h以上的连续性强降水，南北向带状回波持续时间更长，但移动方向与回波长轴方向垂直，且移动速度较快，所以产生的暴雨强度较东西向弱。（5） 地面中尺度辐合线是触发中尺度对流系统的主要原因，河套地区的复杂地形及低空急流的脉动进一步促进了对流触发，地面中尺度辐合线与阴山山脉呈现几乎重叠的分布，有利于降水的持续，促使本次对流暴雨过程的发生。

Based on conventional observation data, FY4A satellite cloud pictures, Doppler radar data, and reanalysis data, the occurrence and various characteristics of the mesoscale convective system (MCS) of the heavy rain process in the Hetao area of Inner Mongolia on July 19, 2018, were analyzed. The results show that: (1) The stable and less moving subtropical high, the 500hPa upper trough, the low-level shear line, the low-level southwest jet, the 300 hPa upper-altitude jet, and the surface low pressure provide a favorable circulation background. (2) The stable low-level southwest jet provides enough water vapor transport. Pseudo-equivalent potential temperature high energy tongue, deep warm cloud layer, high-intensity CAPE, cold advection intrusion behind the upper trough, and the unstable air layer together provide better environmental conditions for the heavy rainstorm. (3) The two successively developed MCS caused the heavy rain process. The convective rainstorm is mainly caused by the slow movement of the east-west MCS along the Yinshan Mountains, 20 mm·h^-1 heavy rain appears at the edge of upwind cloud clusters and the strong TBB gradient areas. (4) The east-west echo moves slowly along the direction of the echo wavelength axis. The strong echo moves slowly from west to east to form a significant “train effect,” causing continuous heavy rain for more than five hours. The north-south direction echo lasts longer, but its moving direction is vertical to the direction of the echo wavelength axis, and the moving speed is faster, so the intensity of the rainstorm produced is weaker than the east-west direction. (5) The surface convergence line is the main factor that triggered the MCS occurrence and development, Hetao area complex terrain, and the pulsation of the low-level jet both promote the effect. The almost overlapping distribution of the surface mesoscale convergence line and the Yinshan Mountains are favorable to the continuation of rain and the convective rainstorm.