Compaction degree is an important factor that affects the mechanical property of reinforced soil. In this paper, two kinds of geogrids were adopted to study the compression performance of cylinder reinforced soil without lateral confinement. Through a single-stage loading/unloading way, the variation rules of vertical deformation for reinforced specimens with the compaction degree of 85%, 90%, and 100% were tested. The following conclusions can be drawn from the present study. 1) Improvement of the compaction degree effectively enhances the soil resistance to deformation, makes the soil deformation stable faster, and makes the velocity curve of deformation more smooth; 2) The impact of compaction degree on the mechanics performance of reinforced soil is closely related to the tensile modulus of reinforced materials and the effective contact area between reinforced materials and soil. Reinforced material with higher tensile modulus provides more effective restrain on the soil.