The degradation of rock masses under freeze-thaw cycles in cold regions presents a serious threat to the safety and stability of engineering structures. The mechanical properties and energy evolution of sandstone with different saturation levels and damage degrees under freeze-thaw cycles were investigated. Uniaxial cyclic loading tests were conducted using the rock top multi-field coupled test apparatus. The results show that as saturation and damage values increase, the peak strength of freeze-thawed sandstone decreases significantly, while the peak strain increases, and the failure mode shifts from brittle to ductile. The elastic modulus decreases progressively with the number of cycles and damage values, displaying a three-stage decay pattern: sharp decline, gradual decline, and accelerated decline. With increasing cycles, saturation, and damage values, the elastic strain energy is gradually converted into dissipated energy. Higher saturation and damage values result in greater cumulative and dissipated energy ratios. Scanning electron microscopy (SEM) observations reveal that the number of cracks and pores increases significantly with freeze-thaw cycles, saturation, and damage values, leading to severe microstructural degradation, especially under high damage conditions where crack connectivity is notably enhanced. This study demonstrates that the synergistic effect of saturation and damage values is a critical factor in the macroscopic mechanical degradation of freeze-thawed sandstone. The findings offer theoretical support for the design and risk mitigation of rock mass engineering in cold regions.