Abstract: The physical and mechanical properties of loess at different regions in China have significant differences. Based on the data from ordinary triaxial test of Yan'an Q2 loess under different confining pressures and misture contents, this paper establishes the constitutive model of triaxial statistical damage for Yan'an Q2 loess by introducing rock statistical damage theory in the damage constitutive model of Yan'an Q2 loess. In the meantime, the paper considers the effect of damage threshold on Yan'an Q2 loess damage variable as well. In addition, the parameters in damage constructive equation are calculated by linear regression on the test results. The experiment and analysis present that in semilogarithmic coordinates, the initial damage point is the peak inflection point of triaxial stress-strain curve of Yan'an Q2 loess. The corresponding value of damage point is also the damage stress threshold. The Yan'an Q2 loess cannot damage and the stress and strain can be in linear elastic relationship when applied stress is less than damage threshold. Conversely, Yan'an Q2 loess can begin to damage. And the damage of Yan'an Q2 loess can enlarge with the increase of applied stress. Finally, statistical damage curve shows good agreements with test curve. This paper indicates that with the consideration of damage threshold, loess statistical damage constitutive model can better reflect the characteristics of Yan'an Q2 loess deformation and failure, with a reference for geotechnical engineering design in the loess plateau.