Objective To explore a method for establishment of tethered cord syndrome model with neural axial stretch in pig. Methods Eighteen adult pigs were randomized into three groups. Sham group:L_1-5 spinal cords were exposed; control group:L_1-5 bilateral pedicle screws were placed after exposure of L_1-5 spinal cords; and experiment group:L_1-5 spinal cords were exposed, then bilateral pedicle screws were placed, and finally L_1-5 intervertebral spaces were extended axially, with six in each group. At different time points, the pigs in the three groups were subjected to X-ray, hindlimb behaviors, urodynamics, somatosensory evoked potential, laser speckle imaging for blood flow and histopathology examination, and the examination results were compared and analyzed. Results In the sham group and control group, there was no obvious change in L_1-5 intervertebral space height, hindlimb motor nerve function scores, urodynamics, somatosensory evoked potentials or laser speckle imaging for blood flow before and after operation; and the spinal cord and nerve structure were normal or nearly normal in the histopathology. In the experiment group, compared with before distraction, L_1-5 intervertebral height after distraction was significantly increased, hindlimb motor nerve function score was significantly decreased, latency of P-wave of sematosensory evoked potential was significantly extended and the amplitude was significantly decreased, and blood flow on the surface of spinal cord was significantly reduced (P<0.05). We observed low compliance bladder, detrusor-sphincter dyssynergia, varying degrees of neuronal necrosis in the spinal cord, vacuolar degeneration and granular degeneration in the cytoplasm, tissue edema, sparse cell structure, and partial perineurium injury in nerve root after extension of L_1-5 intervertebral height. Conclusion The spinal cord and nerve root injury model can be established by loosening posterior column structure and extending intervertebral space, and this model can be used to simulate the clinical tethered cord syndrome patients with sensory and motor dysfunction in the lower extremities, and sphincter dysfunction, which lays a foundation for studying the pathological mechanism and exploring the surgical treatment of tethered cord syndrome.