In the Lower Paleozoic marine facies of the middle-upper Yangtze area of China, there develop sets of mud shale source rocks. They become the important areas of the shale gas exploration and development in the south of China. On the basis of classifying the genetic types of oil and gas reservoirs, the authors consider that this mud shale oil and gas reservoir belongs to one of the source rock oil and gas reservoirs. Based on controlling the main geological parameters of the source rock type gas reservoir distribution, the authors analyse the distribution characteristics of the content of TOC, the mass fraction of TOC (V0;oc))2% shale rock thickness and Ro of the two rich in organic shale reservoirs in Qiongzhusi Group and Niutitang Group of the middle-upper Yangtze area. The authors think that the abundance of organic mass of these two reservoirs is high, the degree of thermal evolution is high and the distribution of the mud shale in the two strata is wide based on the analysis results and that these two reservoirs have the basic geological conditions for the occurrence of shale gas. Based on the characteristics of the shale reservoir distribution, it can be sure that the favorable exploration blocks of the Qiongzhusi Group and Niutitang Group mud shale gas reservoir are located in South Sichuan, North Guizhou, and West Hubei, and that of the Longmaxi mud shale gas reservoir in South Sichuan-North Yunnan, East Sichuan-West Hubei and North Sichuan.