<p>In the Chinese Loess Plateau with crisscrossing gullies and ravines, the under-compacted and weakly cemented loess strata are prone to collapse and landslide disasters. It is crucial to understand the mechanical properties of loess. The past climate change has affected the microstructure of loess, resulting in different mechanical properties. However, few studies have linked past sedimentation and pedogenesis processes with current mechanical properties. Exploring the relationship between the mechanical properties of loess and climate change is beneficial for providing a reference for engineering construction in the loess region, thereby helping to regulate human activities reasonably. This study takes a primary loess-paleosol sequence with a thickness of 21.9&#xa0;m as the research object. Through field sampling, laboratory experiments and data analysis, the abundant precipitation promotes the enhancement of soil mechanical stability, and the formation mechanism of the mechanical properties of loess-paleosol sequences under pedogenesis is supplemented and verified. This research indicates that Quaternary cold-dry/warm-wet climate change is the driving force that shapes the loess mechanical structures, and the weathering pedogenesis plays a dominant role in the mechanical properties of loess. The effect of pedogenesis on mechanical properties is primarily reflected in two aspects, with the contents of clay, calcium carbonate, and iron oxide being the primary factors: (1) the effect of decarbonatization on the collapsibility and compressibility; (2) the particle cementation caused by the adhesion effect enhances the shear strength. This study helps realize the practical application of Quaternary paleoclimate research and provides a data foundation for loess engineering and tillage research.</p>