Expansive soils exhibit significant volume change when experiencing variation of temperature or moisture change. However, previous constitutive models on expansive soil mainly focus on hydraulic conditions, less attention on thermal field. This study delves into the thermo-hydro-mechanical behavior of expansive soils, crucial for applications such as nuclear waste disposal and thermal energy storage. A novel constitutive model, extended from bounding surface plasticity theory, is introduced to simulate the expansive soil behavior under various temperatures. A new approach on effective stress principle considering the effect of temperature is proposed. In this model, changes on suction and temperature are considered, which are in response to mechanical behaviors. Validated by temperature-controlled tests from (Tang et al. in Géotechnique 58:45–54 [1]), the proposed model shows potential in understanding the complex coupling of thermal, hydraulic, and mechanical processes in expansive soils, especially in cyclic environmental conditions.