All fronts cubage of cut soft rock along Wu-Guang passenger express railway for special use takes up more than 60 %. And whether it can be used as filling of subgrade，it has enormous affection on construction costs and environmental protection. Through the indoor CBR experiment studies on the two kinds representative slate filling，its characteristic and influencing factor has analyzed, the implement of “nonrepeatitive double factor variance analysis”in“analysis tool storage room”of EXCEL carries out analysis on the significance of various influencing factor and provides a reference to Wu-Guang railway and relevance project construction.