To study the development characteristics of shale fracture-microfracture system，the main controlling factors and their influences on shale gas seepage and accumulation，fractures were divided into five types according to their morphology based on core and thin section observation and statistics，including bedding fractures，cut-layer high angle fractures，internal high angle fractures，internal low angle fractures and microfractures. Through analyzing effects of multi-parameters on fracture-microfracture，it is considered that the main factors controlling the generation and development of reservoir fracture-microfracture system include the brittleness mineral content，tectonic action，internal structure of rock and its heterogeneity，mechanics characteristics and formation confining pressure. And then combining with the fracture types and main controlling factors，the evaluation of reservoir cracks was done comprehensively. The horizontal cracks，such as the bedding fracture，can enhance lateral diffusion effect，and thus significantly promote the shale gas seepage and accumulation. Especially for those areas that experienced strong tectonic deformation and developed fold structures in southern China region，the lateral diffusion effect caused by bedding fractures and low angle fractures is obvious. Syncline and anticline shale gas reservoirs，which combine characteristics of both the North American shale gas reservoir（self-sourced and in-situ accumulation）and the traditional oil and gas reservoirs（hydrocarbon enriched at the high point of the structure），belong to composite accumulation pattern. In a closed petroleum system，developed fracture network often can make free gas seepage along fracture through lateral diffusion and gas reservoir is formed at the high point of the structure.