In order to establish the mechanics constitutive models of ice in different conditions (i.e., temperature, loading rate, and confining pressure), through the theoretical analysis and experimental research, we compared the characteristics of ice stress-strain curve in uniaxial compression test and triaxial compression test under proportional loading condition. Then, we described the relationship between stress and strain of ice by adopting the mechanics constitutive model of power hardening. Moreover, according to the data from the triaxial compression tests, we established the mechanics constitutive models in the two test conditions by using least squares curve fitting. Overall, the error analysis showed that the mechanics constitutive model of ice is comparatively accurate.