In order to study the mechanical properties of loose deposits, which are commonly found in the process of tunnel construction, by adopting indoor test methods, a compaction test and a direct shear test have been conducted in the representative area of the sampled Yuanbaoshan tunnel in Lixiang railway construction. The results show that the loose deposits of Yuanbaoshan tunnel is characterized with a large discreteness and discontinuous gradation of the grain composition, with its particle size greater than 2 mm, and the mass fraction approximately accounting for 50%. The results of compaction test show that the degree of compaction is an important factor to improve the shearing strength of the tunnel. The friction angle and cohesion of loose deposits in Yuanbaoshan tunnel increase remarkably with the increase of its compactness, with the degree of compaction, normal stress and shearing strength basically positively related. With the degree of compaction being 0.9 and the normal normal stress 250 kPa, the shearing strength of the sample reaches the maximum value of 298 kPa. The analysis shows that the compactness of loose deposits is an important contributing factors of landslide, and the increase of degree of compaction is an important means to increase the shearing strength index of loose deposits.