The discrete element method (DEM) was used to analyze the liquefaction behavior of initially anisotropic sand under nonsymmetric cyclic loading. Ellipsoidal particles were generated to prepare anisotropic sand samples, and undrained cyclic triaxial shear simulations were conducted by using constant volume method. The evolution of mechanical coordination number, redundancy index and fabric anisotropy during cyclic loading was studied, and the liquefaction characteristics of sand at the microscopic level was revealed. The results show that the DEM simulations effectively reflect that dense sand exhibits higher liquefaction resistance under nonsymmetric cyclic loading conditions. When sand undergoes full liquefaction, the mechanical coordination number and redundancy index decrease to 0.35 and 2.4, respectively, regardless of whether the cyclic loading is symmetrical. Under different loading conditions, the particle orientation fabric transitions from anisotropic to isotropic with cyclic loading. Under stress reversal conditions, once liquefaction occurs, the anisotropy of the particle orientation fabric rapidly decreases, while the contact normal fabric changes significantly and shows a directional switch. Initial liquefaction occurs as the contactnormal fabric anisotropy variable transitions from a negative value to near zero. These findings provide an in-depth understanding of the micromechanical mechanisms of liquefaction, contributing to the development of macroscopic constitutive models for cyclic liquefaction of anisotropic sands under complex loading conditions.