Uniaxial and triaxial creep experiments of soft rocks aredone by Chen Applying Method and the Instron-1346 eletronic-fluid serving compression machine. The authors use the five-substance model and discuss the one and three-dimentional constitutive equations and creep ones. It is found that the new model well describes the full creep procedure of soft rocks. The rheological parameters of the creep equations are calculated by the Marquart Method and the forecast curves are drawn. In comprison with the experimental curves,the theorial results are proved.