Abstract: As regards the support problem of large cross section compound mudstone roof starting cut in Bailong colliery, the combined support system with pre-stress truss cable is put forward for the controlling of surrounding rocks of roadway on large cross-section. This article investigates the mechanism of the composite support system with pre-stress truss cable, combined with the practical production and adopting a computer numerical simulation to make a parameters optimal design of the truss cable combination support scheme. The scheme has been successfully used in No. 2-1101 fully mechanized face starting cut of Bailong colliery. This generates significant technology and economic benefits, with good prospects for promoting and application.