This paper provides a comprehensive review of the recent research development and applications of optical cavity enhanced absorption spectroscopy. It has been well understood in physics that the resonance phenomenon is one of the fundamental principles in various disciplines. It boasts of its powerful capability to filter, amplify, and select signals of specific frequencies. The optical cavity, with its periodic transmission characteristics of only certain frequencies of light, is essentially an optical resonance device.In this review, we provide a summary and logical insights into the recent development progress of Cavity Enhanced Absorption Spectroscopy (CEAS). While the term CEAS has been used to refer to all absorption spectroscopy techniques using an optical cavity in the broader sense, we limit ourselves in this paper to the specific category of techniques that use the transmitted light intensity through the cavity to infer properties of the media. The CEAS technology has the advantages of having a fast response time, high measurement accuracy and reduced space occupation. These allow it to play an important role in spectroscopy and trace gas detection in various applications. The theoretical derivation introduces the principle of signal enhancement by cavity enhancement technique and the diagnostic methods for media absorption. The difference between coherent and incoherent signal enhancement is analyzed to guide further discussion of the technical implementation. Based on this, the development of cavity enhanced absorption spectroscopy, including coherent off-axis CEAS, three-mirror structure CEAS, incoherent optical CEAS and optical comb CEAS, is introduced. This section is based upon the two main demands for species detection with spectroscopic techniques, namely, signal enhancement for trace gas detection and precise spectral measurement, and more spectral information over a broader spectral range for speciation and potentially multi-parameter diagnostics. Such demands have guided the relevant methodologies to be developed into coherent CEAS (on-and off-axis schemes, multi-mirror schemes, etc.), incoherent CEAS (with broadband light sources), and the use in combination with optical frequency comb as a coherent but broadband light source. The characteristics, advantages and main development courses of several main technical systems derived from the development of this method under different requirements are discussed. After that, the main application progress of cavity-enhanced absorption spectroscopy is reviewed from three aspects: atmospheric sensing, biomedical sensing, and chemical kinetics diagnostics. The state-of-the-art achievements in each of these fields are reviewed and summarized. Finally, the future development of cavity enhanced absorption spectroscopy has prospected.In all, by reviewing the design guidelines, recent technological advancements and research achievements of cavity enhanced absorption spectroscopy, this review aims to provide a comprehensive and useful reference for researchers and engineers in relevant research and application fields.