Research conclusions:The systematical studies are done on the engineering characteristics of red rock as filling materia,l the compactness and subsidence of red rock subgrade and the characteristics of accumulated deformation through indoor soilmechanics tes,t on -site subgrade filling tes,t subgrade centrifugalmodel tes,t on -site prototype subgrade subsidence observation and on -site prototype subgrade cycle loading tes.t Based on the study, the engineering technology for filling the subgrade ofhigh -speed railwaywith red rock isproposed, including themanufacture standard of red rock fillingmateria,l the compactness standard of red rock subgrade, the structure and design parameters of red rock subgrade, construction technique and construction key points. The engineering practice shows the technology presented in this paper for filling the subgrade ofhigh -speed railwaywith red rock is reasonable and feasible.