Focused on the Lower Cambrian Qiongzhusi formation shale outcrops investigation, sampling and laboratory analysis in middle and upper Yangtze region. Studies show that the Lower Cambrian has thick black shale (50-400 m), excessive organic carbon content (the average is 1. 92%-2. 35% ) ,a high degree of thermal evolution (the average is 2. 0%-4. 0%), a formation with good potential shale gas resources. According to analysis the distribution character of shale thickness-, organic carbon content, maturity, mineral composition, pore and gas-bearing in the research area, optimized three shale gas exploration potential areas; southern Sichuan-western Guizhou, Micangshan-Daba Mountain foreland and western Hubei-eastern Chongqing-northern Guizhou, and evaluated shale gas potential resource in each area. [ABSTRACT FROM AUTHOR]