Constitutive modeling for frozen soil is an important topic for the mechanics of frozen soils and for construction activities in permafrost regions. This study, with the help of hypoplasticity theory, presents three constitutive models for frozen soils. The first model, called extended hypoplastic constitutive model, is obtained by introducing a temperature-dependent cohesion tensor and a deformation-related scalar function into the pioneer model developed by Wu (1992). Then by simulating some triaxial compression tests at different temperatures and confining pressures, the extended model is shown to have a good ability in describing the strength behavior and volumetric change of frozen soil. However, this model is rate-independent and thus cannot account for the loading rate effect and rheological properties of frozen soil. In view of this, the second model, named as visco-hypoplastic constitutive model, is then developed. This viscous model is obtained by dividing the stress rate into a statical and a dynamical part, which are represented by the extended model and a high order model with respect to strain, respectively. Then the versatility of this viscous model is verified by simulating some compression tests at different loading rates and creep tests at different stress levels. The third model, termed hypoplastic creep model, is developed especially for the rheological properties of frozen soil. By simulating some compression creep tests, this creep model is also shown to be capable of describing the creep behaviors of frozen soil, e.g. the time to creep failure and the minimum creep rate in the secondary creep stage. Besides, the relaxation of creep strength of frozen soil can also be described by this creep model.