Using conventional obser-vation data, NCEP1° ×1° reanalysis data, rainfall data of ground automatic weather stations, satellite cloud imagery and radar composite reflectivity factor, this paper analyzed the continuous rainfall of Loudi City from July 14 to 17, 2012 from the perspectives of circulation back-ground, formation mechanism, radar e-cho, and satellite cloud imagery features. The results showed that short-wave troughs moved eastward continuously in middle and high latitude, subtropical high and low-level shear line remained stable, low-level southwest jet grew pow-erful, providing a large-scale favorable circulation background for the continu-ous rainstorm. Rainstorm occurred under the influence of mesoscale echo clusters and echo strips, and mesoscale convec-tive cloud clusters. Mesoscale convective echo or cloud clusters always occurred at the convergence of multiple synoptic scale systems, so they have indicative significance for the rainstorm forecast. Water vapor convergence run through the whole rainfall process, and as the strong humidity center appeared in the low lev-el, heavy rainfall occurred. Mesoscale convection system was demonstrated as ascending motion in the whole tropo-sphere, and rainstorm area was in the intensive belt with increasingly high CAPE value gradient, while increasingly stronger low-level θse frontal zone pro-vided a favorable instable condition for the occurrence of severe convective rain-fall.%利用常规观测资料、NCEP1°×1°再分析资料、地面自动站降水实况资料以及卫星云图资料和雷达组合反射率因子资料等，从环流背景、形成机理、雷达回波与卫星云图特征等方面，对2012年7月14—17日娄底市持续性暴雨进行综合分析。结果表明，中高纬度不断有短波槽东移，副热带高压和中低层切变线稳定维持，低空西南急流发展强盛，是持续性暴雨发生的有利大尺度环流背景；在中尺度回波团或回波带及中尺度对流云团的影响下产生暴雨；中尺度对流回波或云团一般发生在多个天气尺度系统的汇合处，对暴雨预报有一定的指示意义；水汽辐合贯穿整个降水过程，在低层出现强湿度中心时，对应强降水发生；中尺度对流系统表现在整个对流层为上升运动，暴雨区位于CAPE值梯度不断加大的密集带中，低层θse锋区不断增强为对流性强降水发生提供了有利的不稳定条件。
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