Abstract: Taking the roof fall accident caused by small fault structure in 20322 belt roadway in Wangjialing Coal Mine as the engineering background，field investigation was carried out on the the roof deformation and failure characteristics before the roof fall and the characteristics of the fall zone height after the roof fall，and based on this，analysis was made on the bed separation of the roof with different lithology by using RFPA numerical software．The analysis results showed that with the increase of the roof strength and stiffness，the roof stability was significantly improved．The technology of using the high prestressed multi－cable truss system to control the roof stability was proposed and analysis was carried out on its control effect and rational support parameters from the angle of mechanics．After the implementation of the symmetric support scheme by“multibeam anchor cable reinforced composite”，6 places where the roof was rather broken were selected for strata control observation，the observation results showed that the roof control effect was good．