In order to solve the mechanical characteristics in the construction of pile-beam-arch method in loess stratum, this paper carried out laboratory tests, focusing on the mechanical behavior of loess under different water content. Through uniaxial and triaxial compression tests, the variation patterns of key parameters such as compressive strength, elastic modulus, cohesive force, and internal friction angle of loess samples were analyzed in detail. The results show that the compressive strength and elastic modulus of loess decrease significantly with the increase of water content, and the cohesion and internal friction angle also show a downward trend. These experimental results not only reveal the internal mechanism of the change of mechanical properties of loess with water content, but also provide an important theoretical and experimental basis for the construction of subway stations in the loess area.