Abstract: Non-equilibrium atmospheric pressure plasma has received much attention for various applications, such as biomedicine, environment, and material processing. The various reactive particles in the plasma often play an important role in these applications, thus the diagnosis of the concentrations of these particles is important to promote these applications. This paper gives a detailed review of an important non-equilibrium atmospheric pressure plasma diagnosis method, namely, laser-induced fluorescence. Firstly, the basic principle and typical experimental setup of laser-induced fluorescence are described. Secondly, the absolute density calibration processes and experiment details of single-photon and two-photon excitation cases are given. Thirdly, for the widely used reactive particles including OH, NO, O, and N, the characteristics of the temporal resolved evolution and spatial resolved distribution are analyzed and discussed. Finally, according to the characteristics and research status of laser-induced fluorescence technology, the future research directions are analyzed and discussed.