In order to improve and develop the research system of inlet swirl distortion of aero-engine, the generation and source of inlet swirl distortion were reviewed, and the methods of simulating swirl distortion at home and abroad were summarized. The influences of swirl distortion of different types and structures on the performance and stability of compressors and aero-engines were summarized. The existing problems and difficulties in the current study of swirl distortion were analyzed synthetically, and the development trend of swirl distortion was discussed. Following suggestions are given: a variable swirl distortion generator should be developed. It is necessary to investigate the influence mechanism of swirl distortion on engine performance to lay a foundation for extending stable working range of engine effectively. Many ways should be used to extend stable working range of compressor/engine under the condition of inlet swirl. A unified evaluation index of swirl distortion should be established and incorporated into the integrated distortion index system. The design method of small distortion inlet should be explored.