Abstract: Based on drilling core samples, X-ray diffraction, organic carbon, vitrinite reflectance and other tests were used to explore the characteristics of the composition, brittleness and depositional control of mudstone in coal measures form well 1001 in Huainan mining area. The results show the TOC content of the mud shale is low, ranging between 0.6%~6.05%, with an average of 2.44%. Kerogen is mainly of type, Ⅲ a few of kerogen is of type Ⅱb, kerogen is in oil generation window and range of moisture generation, has suitable conditions for gas generation. The mineral composition of shale is dominated by quartz and clay minerals, brittleness index ranged from 20% to 60%, with the average of 45%. The shale is hard, showing good fracture resistance, it has the potential transformation. Hypoxic environment is conducive to the development of brittle minerals, playing a positive role to the brittleness of shale. When marine environment changed into terrestrial environment, during the transition, clay mineral content increased, brittle mineral content decreased, which plays a negative role to the brittleness of shale. Reductive depositional environment is conducive to the well, shale brittleness increased, obviously the results may be subject to burial diagenesis largely, which need to be further explored.