Abstract: The geocell is a new type of three-dimensional reinforced geotechnical material to restrain the lateral deformation of the soil to enhance the bearing capacity of structure and reduce its deformation. At present, the worldwide investigations on geocells are mainly focused on their engineering applications and reinforcement mechanism, while limited investigations are conducted on themselves, especially the tensile mechanical properties of the strips. The uniaxial tensile tests are conducted on the geocell strips made from high-density polyethylene (HDPE), polypropylene (PP) and polyester (PET). The effects of the shapes (Type I-dumbbell, Type II-rectangular) and sizes (Type II-rectangular, Type III-rectangular) of the specimens on the strength and deformation characteristics of geocell strips are studied, and the micro-analysis on the failure geocell strips is performed. It is determined that the elongation rates of the HDPE, PP and PET geocell strips are sensitive to the specimen shape. The elongation of Type I-dumbbell is smaller than that of Type II-rectangular. The shape and size of the specimens have some effects on the strength of the HDPE geocell strips. The strengths of PP and PET geocell strips are greatly affected by the specimen shape. The tensile strength of Type I-dumbbell is smaller than that of Type II-rectangular. The fractured surface of HDPE geocell has rough surface and obvious plastic yield deformation. The microfibril bundles on the fractured surface of the PP geocell are neatly arranged, and the microfibrils are randomly distributed. The fractured surface of PET geocell is smooth. The test results can provide reference for the study on reinforcement mechanism of the geocells.