The single crystal blade laser repair technology reduced considerable cost in the aviation field. This technology is based on the additive manufacturing process, in order to grow an ideal single crystal structure through directional solidification on the single crystal substrate. At present, the mainstream single crystal blade repair technology includes the following two categories: Directed Energy Deposition (DED), Powder Bed Fusion (PBF). In this paper, the research progress of two main repair technologies is reviewed, the influence of process parameters and the mechanism of single crystal growth in the repair process are summarized, and the application potential of single crystal repair technology in the aerospace field is clarified. In addition, this paper also discusses the main challenges currently faced by single crystal blade repair then looks forward to its future development trend.