Research conclusions:(1)Because the complicated material composition and characteristic，systematically experiment should be done in order to evaluate the adaptability of using soft rock as filling materials for subgrade of high speed railway. The experiment research aspect involve strength，water rational，broken resistance，disintegration，mineral composition，particle analysis and particle variations under external force of the soft rock. (2)The type of soft rock can be used as the filling materials for high speed railway subgrade，which can be easily broken，different to soften，not excluding harmful materials like montmorillonite.(3)The non-uniform weathering soft rock cant be used as the filling materials directly. The adaptability of non-uniform weathering soft rock after improved，was dependent on the broken resistance，disintegration，mineral composition and particle analysis of it. The adaptability of the completely weathered soft rock can refer to the soil filling classification standard distinguished by the mineral and particle composition. (4)The group classification standard of the soft rock stone and the evaluation method of filling the subgrade of high speed railway in this paper with soft rock have an important significance of the high-speed railway in soft rock region.