The mineralogical composition and its influencing factors of three sets of excellent Paleozoic marine source rocks are analyzed to discuss the geological significance of mineralogical composition in the Middle-Upper Yangtze Region (MUYR). The source rocks in the Lower Cambrian Niutitang, Upper Ordovician Wufeng - Lower Silurian Longmaxi, and Upper Permian Dalong Formations are similar in mineralogical compositions, which are siliceous shale of low clay mineral average content. Mineral contents of the Upper Permian Longtan Formation source rocks show much variation. 65% of source samples have over 70% quartz content, and clay shale is found mostly in the Longtan Formation. The difference of mineral components in marine source rock is mainly caused by the sedimentary environment, and it is also greatly influenced by the bioclastic sedimentation and thermal maturity. Different mineral composition is a cause of the difference in hydrocarbon-generating model and hydrocabarbon expulsion rate of source rock. The source rocks of the Niutitang, Wufeng-Longmaxi and Dalong Formations are rich in brittle minerals and poor in clay mineral, which is favorable for exploiting shale gas, but unfavorable for gas adsorption in shale. And it is necessary to differentiate shale source rocks according to the mineral components in the Longtan Formation in shale gas exploration.%系统分析中上扬子古生界3套海相优质烃源岩矿物组成及其影响因素,探讨烃源岩矿物组成所蕴含的油气地质意义.中上扬子古生界下寒武统牛蹄塘组、上奥陶统五峰组—下志留统龙马溪组、上二叠统大隆组优质烃源岩具有相似的矿物组成,主要为硅质型泥页岩,黏土矿物含量低,而上二叠统龙潭组烃源岩矿物组成变化较大.约65％的烃源岩样品中石英含量大于70％,黏土型泥页岩主要发育在龙潭组.海相烃源岩矿物组成的差异主要由沉积环境导致,同时受生物沉积作用、热演化成熟度的影响.矿物组成差异是导致烃源岩生烃模式和排烃能力差异的因素之一.牛蹄塘组、五峰组—龙马溪组、大隆组优质烃源岩富脆性的硅质矿物而低黏土矿物,有利于页岩气的开采,但较低的黏土矿物含量对泥页岩吸附气能力是一种制约因素；龙潭组页岩气勘探应根据其矿物组成的变化在不同区域分别对待.
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