<p>The variation in prestressed anchor cable tension during the overwintering period in deep foundation pits within the paramos freeze–thaw region is critical for the safety of prestressed anchorage structures. This study investigated the evolution of prestressed anchor cable tension due to temperature fluctuations during the overwintering period. The study also analyzed the distribution pattern of anchor cable tension at different heights on the same pile, explored the distribution of tension across different geological strata, and examined the impact of stratum characteristics on anchor cable tension. Based on the differences in frost heave effects between sunny and shaded slopes, we compared the evolution patterns of tension at the same height and stratum on both slopes. Finally, this study discussed the impact of steel bracing, an auxiliary support method, on the evolution of anchor cable tension, elucidating the effects of combined support strategies. This study contributes significantly to understanding how prestressed anchor cables behave under frost heave and temperature changes in deep pits, addressing the real problem of when anchor cables fail over the winter. It provides a good mix of theoretical foundations and practical insights for the safe design and construction of deep pit anchoring support structures in the paramos freeze–thaw region.</p>