Based on pullout tests, the effect of normal stress, compaction degree as well as water content of backfills on interaction mechanism of reinforcement-soil interface and reinforcement displacement were investigated and the evolving pattem of reinforcement displacement was analyzed. The results showed that geogrid displacements along the full-length obviously lagged behind the displacement at loading end, and with increase of distance away from loading end, the geogrids displacements tended to decrease nonlinearly. An increase in normal stress, compaction degree or water content caused to the decrease in geogrid displacement for the identical pullout force and the same measured points. Moreover, the farther the location of measured points is, the weaker the effect of above-mentioned factors on geogrids displacements. During the pullout tests, the main failure modes included the geogrid pulled out fully and breakup failure of geogrid, and the peak pullout forces were approximately linear with the displacement at loading end. The peak pullout forces were closely related with the normal stress, compaction degree, water content or pullout rate. To increase compaction degree or water content of backfills, which caused to enhance interface interaction of reinforcement and soil, contributed somewhat the increase of friction angle of reinforcement-soil interface made the apparent cohesion of interface to increase remarkably, and the apparent cohesion of reinforcement-soil interface reached the greater value when the water content of backfills equals to the optimum water content. The test results showed that it is necessary to strictly control the water content of the backfill soil, and allowing the reinforced structure to deform properly is conducive to playing the role of reinforcement.