Abstract: Among the existing LiDAR technologies, the LiDAR with frequency modulation continuous wave (FMCW) format has the advantages of high resolution, high measurement accuracy, light weight, low power consumption compared with the conventional time-of-flight LiDAR. Benefitting from adopting continuous lightwave for measurement, the FMCW LiDAR also has unique performances such as high sensitivity, rich information, and easy processing and demodulation. It is highly competitive for high-resolution, high-accuracy detection needs, and has the potential for very good integration, miniaturization, and low energy consumption. This paper introduces the basic principles of different LiDAR systems, especially focusing on the important parameters of FMCW LiDAR, and classifies the research work of FMCW LiDAR in the past ten years into different types based on the light source scheme, and discusses the features of various schemes.