Abstract: According to the stress-strain and permeability-strain curves which obtained from the servo penetration test, it analyzed the change characteristics of soft rock permeability with deformation in the process of whole stress and strain, it was concluded that the permeability of samples could be divided into five stages in the process of whole stress and strain. Combined with the fitting curves of soft rock relevance between stress and permeability, it obtained that soft rock permeability had the characteristic of hysteresis, namely the peak of permeability often appeared after the peak of stress. Through the regression analysis which used polynomial and index function equation to study soft rock correlation of stress and permeability, it was concluded that two kinds of function equation fitting correlation was good, and the effect of polynomial fitting was better than the one of index function fitting, but polynomial mathematical expression was relatively complicated.