The black soil region in Northeast China is an important commercial grain base in China. Hydrothermal migration and deformation of the soil during the freeze-thaw process directly affect regional food security and ecological stability. This study systematically revealed the synergistic mechanism of black soil freeze-thaw under multi-factor driving through indoor unidirectional freeze-thaw experiments, scanning electron microscopy observations, and thermal-water-deformation multi-field coupling models. The results showed that under the condition of no water replenishment, the temperature rise of the soil exhibited hysteresis and periodicity, and the supercooling degree of the surface phase change reached 1.2-2.5 ℃; Proactive water replenishment increased the upper layer temperature by 2-4 ℃, reduced freezing depth by 28%-35%, and weakened the negative temperature effect on the ground surface. At the same time, the water field redistribution during the freezing stage showed an "S" shape, with the unfrozen water content decreasing from top to bottom, and the trend during the melting stage reversing. The freeze-thaw cycle significantly changed the microstructure, with a porosity increased by 21.62%-546.47% after 30 cycles, and aggregate destruction rate up to 99%. Moreover, samples with high water content (>32.3%) were more susceptible to freeze-thaw effects. In addition, the constructed multi-field coupling model (temperature and water content correlation coefficient >0.9) accurately predicted the freeze-thaw response, revealing the layered mechanism of surface peat black soil frost heave dominance, middle layer permeability difference regulating heat conduction, and deep rigid skeleton inhibiting deformation. It is recommended to improve soil stability through straw covering, drainage measures, and low water cultivation system. The study results provide theoretical and technical support for the construction of a dynamic monitoring system for freeze-thaw erosion and the optimization of conservation tillage in black soil areas.