A novel double-layer collagen membrane with unequal pore sizes in each layer was designed and tested in this study. The inner, loose layer has about 100-μm-diameter pores, while the outer, compact layer has about 10-μm-diameter pores. In a rat model of incomplete spinal cord injury, a large number of neural stem cells were seeded into the loose layer, which was then adhered to the injured side, and the compact layer was placed against the lateral side. The results showed that the transplantation of neural stem cells in a double-layer collagen membrane with unequal pore sizes promoted the differentiation of neural stem cells, attenuated the pathological lesion, and signiifcantly improved the motor function of the rats with incomplete spinal cord injuries. These experimental ifndings suggest that the transplantation of neural stem cells in a double-lay-er collagen membrane with unequal pore sizes is an effective therapeutic strategy to repair an injured spinal cord.