Based on comprehensive analysis of outcrops observation and sample testing,the formation conditions of shale gas in Lower Silurian Longmaxi formation shale of northern Guizhou were analyzed, such as sedimentary characteristics and distribution, geochemical characteristics, burial thermal evolution and reservoir characteristics. The results show that the Longmaxi formation shale in the study area, characterized by extensive distribution (residual area of about 14 600 km2), big thickness (maximum of up to 200 m), fine kerogen type (sapropel type), rich organic matter content (residual total organic carbon mass fraction w(TOC) of 3.92%), high air content (saturated adsorption amount of 2.77%), high thermal evolution (vitrinite reflectance of 2.68%), appropriate depth (a large area of 1−2 km in depth), high brittleness mineral content(average of 43.2%), strong heterogeneity (great changes of brittleness mineral content in horizontal and vertical), low porosity (concentrated in 4%−10%) and low permeability (average of 0.088×10−3 μm2), have good accumulation potential geological and fracturing mining conditions, and Xishui−Renhuai Areas and Daozhen−Wuchuan−Yanhe Areas are the most favorable exploration zones. Longmaxi formation shale in the study area is abundant in shale gas resources, and the values of resources calculated by probability volume should be (3.52−4.69)×1012 m3, which match well with those obtained by geological analogy method.%在野外地质露头观察和样品测试数据综合分析的基础上，对黔北地区志留系下统龙马溪组页岩的沉积特征及展布、地球化学特征、埋藏热演化史、储层特征等页岩气藏形成条件进行研究。研究结果表明：研究区龙马溪组页岩区域分布广，残余面积约为14600 km2；厚度大，最厚可达200 m；有机质类型好，干酪根为腐泥型；有机质质量分数高，残余有机碳质量分数w(TOC)高达3.92%；含气量好，饱和吸附量高达2.77 m3/t；热演化程度高，镜质体反射率高达2.68%；埋藏深度适中，大部分地区埋深为1~2 km；脆性矿物质量分数高，平均值为43.2%；非均质性强，脆性矿物质量分数横向、纵向上变化都大；孔隙度较低，集中在4%~10%；渗透率低，平均值为0.088×10−3μm2。因此，研究区龙马溪组具备良好的页岩气成藏地质条件和压裂开采条件，习水—仁怀地区和道真—务川—沿河地区为最有利的页岩气勘探区带。研究区龙马溪组页岩资源丰富，运用概率体积法和地质类比法算出的资源量吻合很好，为(3.52~4.69)×1012 m3。
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