Based on the compression and swelling curves at different temperatures, the thermal consolidation phase is substituted by a mechanical consolidation phase, which is of the same deformation. Then, the complex thermomechanical properties of soils have been translated into pure mechanical properties. Further, a new non-associated elastic-plastic consititutive model considering temperature effects is presented by using the traditional critical state theory and non-associated flow rule. The whole model contains six independent parameters, and the physical significance of each parameter is specific and easy to be confirmed through the temperature-controlled triaxial compression test. In addition, with an increase in temperature, the slopes of the compression and swelling curves, the critical state stress ratio and poison ratio have no obvious changes, while the preconsolidation pressure changes exponentially. Otherwise, the trial method is used to determine the scaling factor between the plastic potential and yield equations. Finally, the method of determining each model parameter is put forward in detail on account of the drained temperature-controlled triaxial test for Kaolin and Bourke clays, and the new model is proved to be reasonable by comparing the simulation values and test data.