Spinal cord injury (SCI) represents a complex pathophysiological process involving the interaction of multiple cell types. Conventional sequencing methods can only detect the average gene expression level of the damaged local cell populations, which is difficult to reflect its heterogeneity. Therefore, new technologies are needed to reveal the intercellular heterogeneity and the complex intercellular interactions of the damaged lesions. The single-cell RNA sequencing (scRNA-seq) technique facilitates high-resolution profiling of gene expression at the single-cell level, providing insights into cellular heterogeneity and function, potential molecular pathways, cell fate transitions, and the intercellular interactions pertinent to disease progression. This technology generates valuable gene expression data that support both basic and translational research efforts aiming at the identification of therapeutic targets for intervention. The scRNA-seq technique and its multifaceted application in the local immune microenvironment of injury after SCI were discussed, which will contribute to a more comprehensive understanding of the pathophysiological processes in the immune microenvironment of SCI.