Abstract: Compared with ordinary mudstone,carbon mudstone in Liupanshui has special engineering characteristics.The mechanical characteristics of the area of carbon mudstone are researched in detail through fall cone test to determine liquid limit and plastic limit,compaction tests,shear strength test,and compression test in laboratory.The research results show that ①Carbon mudstone is of good plasticity,under the influence of water softening,it easily comes to disintegrate and lower the intensity; ②The moisture content of carbon mudstone can significantly affect on the compaction performance,dry density changed a lot when moisture content is between 12.5 0% and 15%; ③The cohesive force of carbon mudstone decreases rapidly with the increase of moisture content when it is leas than 11%,and changes little when it is between 11% and 15%; ④Compreasion settlement of carbon mudstone appears after the loading in a short period of time,it can quickly compress and achieve a stable state after the loading.