The integral inertial particle separator is a helicopter air inlet protection device. It has excellent performance and wide application compared with other protection devices, which is of great significance to ensure the regular operation and improve the service life of helicopter engines. This paper summarizes the research progress of integral inertial particle separators, including the following aspects: 1) The classification and aerodynamic parameters of the integral inertial particle separators are introduced. 2)The research methods and their results of the integral inertial particle separators are sorted out. 3)The factors affecting the performance of the integral inertial particle separators are summarized and analyzed. 4)The future development of integral inertial particle separators is predicted. This paper can be the reference for future study and the guide to integral inertial particle separators’ optimization design.