In recent years，with the rapid development of road engineering construction，subgrade settlement caused by vertical compression of compacted loess has become increasingly serious.The previous research on the deformation of compacted loess mostly focuses on moisture content，porosity，saturation，and other aspects，ignoring the influence of lateral constraint conditions and different compaction on compacted loess.To address these issues，based on the reconstruction and expansion project of G 307 road in northern Shaanxi，this paper selected compacted soil samples of subgrade on site to carry out indoor compression tests.By applying different lateral constraint conditions，the stress-strain curves of compacted loess subjected to vertical multistage load under different compactness and confining pressures were analyzed.The results indicate that the vertical compression of soil samples is positively correlated with the applied vertical load and inversely correlated with compactness.Confining pressure and lateral constraint can reduce the vertical compression of soil samples.The results reflect the working state of the soil sample in the actual project，providing reference and guidance for the subgrade filling in the loess region.