Abstract: ‍ ‍Energy is one of the basic elements of human existence， and most of its acquisition comes from the combustion of fossil energy and hydrogen. Problems such as the massive generation of harmful gases and greenhouse gases， low combustion efficiency， and unstable combustion condition are widespread in the current combustion process. Combustion diagnostic technologies analyze the state of the combustion flow field by measuring the physical and chemical properties of the combustion flow field， such as temperature， pressure， material distribution， and so on， and they are effective analysis methods for the above problems， and widely used in major basic research fields such as aerospace， energy， and combustion. In order to avoid the strong influence of the traditional measurement methods which are in contact with the flame flow on the temperature and thermal state of the combustion flow field， the non-contact optical measurement technologies have been favored by scholars and vigorously developed in recent decades. The simultaneous acquisition of spatiotemporal spectral information by optical techniques is the key to the study of combustion technology. However， the current non-contact optical measurement technologies are restricted by information sampling in time， spatial， and spectral domains. Therefore， based on the signal acquisition and processing methods， this paper systematically classifies the representative existing non-contact optical technologies and analyzes the mechanism that the existing technologies cannot achieve simultaneous sampling of spatiotemporal spectra from the perspective of principle. Then， this paper prospects the development of non-contact optical measurement technology. It is believed that the advanced spectral measurement technology can solve the problem of simultaneous sampling of temporal and spatial spectrum well， which is helpful to the further research and development of combustion diagnosis， and can provide new ideas for the future research direction.