Laboratory direct shear test and pullout test were conducted focusing on biaxial geogrid (SS20) and triaxial geogrid（TX160） to investigate the deformation and geogrid-soil interface behavior. The displacements of geogrid specimens were recorded at 4 sections in the pullout test. The development of geogrid-soil interface shear stress, geogrid deformation, shear dilatancy/shrinkage behavior and interface parameters were analyzed, and the effect of test methods on the testing results was also investigated. The results show that the interaction between the geogrid and soil of TX160 concentrates at the vicinity of pullout end. However, this interaction is well developed along the full length of SS20 specimens. Meanwhile, this interaction of TX160 can be better enhanced with the increase of vertical stress compared with that of SS20. Both the peak and residual friction angles of SS20 case are greater than that of TX160 case, while the cohesion is just opposite. The vertical stress has obvious effect on the geogrid-soil interface strength parameters obtained from both the direct shear test and pullout test. Thus, the vertical stress adopted in the test should be determined based on the actual stress status of the geogrid for engineering application.