The soil-rock mixture, a collection of soil particles and rock blocks, is inherently heterogeneous and anisotropic due to sig-nificant particle size and material strength differences. This study conducts triaxial tests on soil-rock mixture samples of various compactness subjected to varying freeze-thaw cycles. A mesoscopic simulation is carried out by particle flow code (PFC) to analyze the effects of freeze-thaw cycles on the mechanical properties of soil and rock particles. The results show that the mechanical properties of the soil-rock mixture under freeze-thaw cycles are greatly affected by the initial compac-tion. In general, when the degree of compaction is higher, the influence of freeze-thaw cycles on the soil-rock mixture is greater. The stress-strain curves of the samples with different compactness demonstrate strain-softening behavior. The freeze-thaw cycles greatly influence the failure strength of the samples with a higher degree of compaction but have little impact on the samples with a lower degree of compaction. On the microscopic level, during freeze-thaw cycles, the pore volume in the highly compacted sample is too small to accommodate the volume expansion from ice crystal formation, causing significant strength loss among the soil and rock particles and deterioration of the macroscopic properties of the soil-rock mixture.