Objective To review the in vivo imaging research progress of two-photon microscopy (TPM) in spinal cord. Methods The recent literature concerning in vivo two-photon imaging of axon, microglia, and calcium in transgenic mice spinal cord was extensively consulted and reviewed. Results In vivo two-photon imaging of spinal cord provide dynamic information about axonal degeneration and regeneration, microglial accumulation, and calcium influx after spinal cord injury. Conclusion TPM in vivo imaging study on spinal cord will provide theoretical foundation for pathophysiologic process of spinal cord injury.