本文分析了西湖凹陷中南部含油气系统基本地质要素和事件 ,认为 :西湖凹陷中南部烃源岩有机质丰度中—高、有机母质类型为III腐殖型 ,储集砂体发育、类型多 ,砂岩具有Ⅱ、Ⅲ类储集条件 ,上覆泥质岩的封盖性能好。在平湖构造带、苏堤构造带烃的生成、运移和圈闭形成在时空上相匹配 ,具良好的油气资源前景。 The paper analyzes the basic geologic elements and events of the petroleum systems in the central and southern part of the Xihu Sag. It is concluded that the organic matter abundance of middle-southern Xihu sag is medium-high, the organic parent is III humus, the reservoir sand body is developed, Sandstone has Class II and III reservoir conditions, and caprock performance of overlying mudstone is good. In the Pinghu structural belt, the formation, migration and trapping of hydrocarbons in the Sudi structural zone are matched in time and space, and have good prospect of oil and gas resources.