Abstract: To address the engineering challenges in compaction control caused by fine particles, non-cohesiveness, and poor water retention of aeolian sand, this study proposes a technical approach of loess admixture to improve the mechanical properties of aeolian sand. Specimens of aeolian sand-loess mixtures with varying compaction degrees, sand contents, and saturation levels are prepared. A series of one-dimensional confined compression tests under different vertical pressures are conducted, complemented by scanning electron microscopy (SEM) and breakage potential calculations, to systematically investigate the compression deformation mechanisms and particle breakage characteristics. The results show that the sand content governs the compression deformation in three stages: at sand content bellows 20%, aeolian sand particles progressively form a spatial skeleton; at 40% sand content, skeleton instability causes deformation exceeding that of pure loess specimens; when the sand content ranges from 40% to 80%, the material behavior transitions from loess-dominated to aeolian sand-dominated modes. Increasing compaction degree enhances the compression modulus and reduces the vertical displacement. Saturation effects exhibit sand content-dependent characteristics. SEM analysis and breakage potential calculations reveal that aeolian sand particles undergo near-complete breakage under a pressure of 100 kPa, with breakage potential showing rapid growth at first and then slowly with the increase of pressure. These findings provide theoretical guidance for land reclamation engineering in aeolian sand regions.