Based on satellite cloud images and conventional observation data,the characteristics of the circu-lation situation and water vapor transportation of the mesoscale convective complex (MCC)in Shaanxi are ana-lyzed.Results show that:MCC occurred in southern Shaanxi accounts for about 80 percent of Shaanxi province’s total,most of them formed in the evening to morning.200 hPa has similar circulation situation:all MCC appeared on the northeastern side of the high-pressure southward,in the warm and wet flow region on northwest side of sub-tropical high pressure;In middle and lower troposphere exist vortex or shear from Gannan to eastern Sichuan;On the ground chart,the hot low pressure in eastern Sichuan and southern Shaanxi is more stable.Cold advection which effect MCC go through eastern part of Gansu intrusion Shaanxi Province,and enhance the baroclinicity of low vortex in middle and lower troposphere and triggered convective;Cloud images feature shows:the majority of MCC formed in Shaanxi are developing and strengthened from convective cell,such MCC appeared in southern Shaanxi heavy rainfall process,with stable and less moving,north extension is not obvious characteristics;Another type of MCC is formed by convection clouds merging,developing and strengthened from new born convective cloud cluster in warm area of cold front cloud,such MCC north extension and move towards east obviously;Cloud Top Brightness Temperature (TBB)displayed:the strong precipitation of MCC in Shaanxi is at the maximum side of the TBB gra-dient,and the maximum hourly rainfall best matches the time of TBB lowest value.Above features are good refer-ence for the study of the flood and rainstorm forecast,early warning and disaster reduction service in Shaanxi.%运用卫星云图、常规观测资料对发生在陕西的中尺度对流复合体（MCC）的环流形势、水汽输送等特征进行分析。结果表明：陕南出现的 MCC 约占全省总数的80％，多形成于傍晚至凌晨。陕西出现 MCC 时，200 hPa 有着相似的环流形势，均出现在南压高压的东北侧、副热带高压西北侧边缘偏南暖湿气流区域；对流层中低层，甘南－四川东部地区都有低涡或切变配合；地面图上四川东部及陕西南部多为稳定少动的热低压，影响MCC 的冷平流多经甘肃东部入侵陕西境内，增强了对流中低层的低涡斜压性进而触发对流。云图特征显示：陕西 MCC 以对流单体发展加强形成的居多，这类 MCC 多出现在陕南强降水过程中，具有稳定少动、北伸不明显的特征；也有对流云团合并、冷锋云前部暖区新生对流云团发展加强形成的 MCC，该类 MCC 北伸、东移相对明显。云顶亮温（TBB）显示：陕西 MCC 的强降水出现在 TBB 梯度最大一侧，最大小时降雨量与 TBB 的最低时段对应较好。上述特征对研究陕西致洪暴雨的预报、预警及防灾减灾服务具有很好的借鉴作用。
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