Abstract: Accurately determining the yield stress of soil is crucial in geotechnical engineering. However, traditional methods, such as the Casagrande method, have a series of problems, including sensitivity to sample disturbance and the subjectivity of manual operation. This paper aims to propose a more accurate and objective method for determining the yield stress of unsaturated soils based on dissipated energy. Firstly, the deformation work during the one-dimensional compression process of unsaturated soils is analyzed, and its dissipated energy expression is derived. The relationship between dissipated energy and net stress is then used to determine the yield stress. Subsequently, through compression experimental results, the required parameters are obtained, dissipated energy is calculated, and thus the dissipated energy-effective stress relationship curve is obtained. The yield stress of unsaturated soils can be determined from the inflection point of the dissipated energy versus vertical stress change curve. The yield stress values determined by the dissipated energy method are compared with traditional graphical methods, showing high consistency. The abrupt change in the turning point of the dissipated energy curve is influenced by compaction and saturation, revealing the impact of the pore structure state controlled by compaction and the matric suction state controlled by saturation on the soil's yield behavior. The dissipated energy method has a more rigorous theoretical foundation, with clear inflection points across the entire saturation range, significantly reducing subjective judgment and fitting errors. It can serve as a strong supplement or even an alternative to traditional methods.