Granular soils possess anisotropic internal structure (or termed fabric) because of gravity effect in the deposition process, which may significantly affect their mechanical behaviour and relevant geostructures. The fabric anisotropy is always a paramount ingredient when developing any sophisticated and full-fledged constitutive models for granular soils. In this study, the anisotropic critical state theory (Li and Dafalias, 2012) is incorporated into the hypoplastic model to describe the anisotropic sand behaviour under different loading conditions. A deviatoric fabric tensor is employed to characterize the internal structure of sand, and it evolves toward the loading direction following a simple evolution rule. A scalar-valued fabric anisotropic variable indicating the interplay between the fabric and the loading direction is introduced into the model to account for the impact of fabric anisotropy on the dilatancy and strength of sand. The model is further extended to different loading conditions by introducing several constitutive mechanisms. The fabric change effect is properly considered to simulate the liquefaction phenomenon and strain accumulation of sand under undrained cyclic loading. The fabric tensor is incorporated into the hypoplastic flow direction to reproduce the non-coaxial response. The tangential loading effect can reflect the stiffness degradation of sand under undrained rotational shear conditions. The model is capable of simulating the anisotropic responses under different loading conditions, including monotonic loading, cyclic loading, and rotation of principal stress direction, which are in reasonable agreement with the available experimental data.