Abstract: Using an improved permeation test device, the effect of macro steel fiber(SF) content and load level on the permeability of concrete(NC) subjected to uniaxial compression was studied, and the data of test were fitted and analyzed. The effect of load level on damage of SF/NC was studied by ultrasonic testing. The results indicate that the permeability of NC is related to the load level, and there exists a threshold value for the applied load level. The addition of macro SF delays the threshold value, and the threshold value increases with fiber content within a certain range. When the fiber content is 0, 20, 40 and 60 kg/m³, the threshold value is about 0.6, 0.7, 0.7 and 0.8, respectively. The effect of load level on the ultrasonic pulse velocity of NC is similar to permeability coefficient, which can be used to evaluate the permeability of NC under uniaxial compression.