Abstract: A series of gas and saturated penetration tests for the Malan loess are conducted by using the improved ZC-2015 air permeameter and TST-55 permeameter. We firstly determine the stable permeability diameter of the corresponding ka, and then explore the relationship between air permeability ka and saturation coefficient of permeability Kw. The research results show that ka not only describes the pore and structural characteristics of unsaturated soils, but also can be used to predict Kw. ka decreases with the increasing permeability diameter, and ultimately this trend becomes stabilized. The stable permeability of the undisturbed and remolded loess is 8 cm. There is a significant double-logarithmic linear relationship between ka and Kw, The correlation between lgka and lgKw of the remolded loess with different grain compositions and undisturbed loess in different depths are obvious, but the fitting formula between the undisturbed soil and the remolded soil is very different. In addition, when the content of clay particles is high, the slope β and intercept α of the remolded sample obviously increase. Under the different water content, the formula of the remolded soil is very different. when the water content, the change in ka is more than Kw with the increase of the dry density, and the slope β and the intercept α of fitting line are obviously reduce.