Abstract: Coal,as an important fossil fuel,has abundant reserves. Despite the rapid development of new and renewable energy,coal resources will continue to be an important part of China's primary energy in the coming decades. However,the utilization of coal brings a lot of environmental pollution problems. As a result,the utilization of China ' s coal resources gradually transforms to the high efficiency,low carbon,and low NOxtechnology. With the rapid development of optical diagnostics technology,a variety of in situ non-invasive optical diagnostic techniques that is suitable for pulverized coal combustion diagnosis have emerged,which greatly promotes the development of the combustion science and provides more experimental methods for the clean and efficient utilization of coal. In this paper,the research progress of optical diagnosis on ignition and combustion characteristics of pulverized coal in different ways at home and abroad was introduced. The optical diagnostics research progress on ignition and combustion process of pulverized coal for both single particle and particle streams was summarized. At present,the optical diagnostic techniques used for pulverized coal combustion includes: full spectrum imaging,CH*/C2*chemiluminescence imaging,planar laser induced fluorescence( PLIF),double color/three-color pyrometer,Mie scattering,laser induced incandescence( LII),coherent anti stokes Raman spectroscopy( CARS),laser-induced breakdown spectroscopy( LIBS) and so on.The optical diagnosis research on ignition delay,devolatilization,volatile combustion,ignition mode,environmental factors( ambient temperature,oxygen concentration,atmosphere),oxy-fuel combustion,oxy-steam combustion,the release of alkali metals for both single particle and particle streams was analyzed to provide theoretical and experimental foundation for clean and efficient utilization of coal. The ignition and combustion characteristics of pyrolyzed char and Shenhua bituminous coal blended fuel were studied by using OH-PLIF and three-color pyrometer. Considering the ignition delay and the burnout ratio of the blending,the optimal blending ratio of pyrolyzed char is20%,which provides a reference for actual industrial application of pyrolyzed char. OH-PLIF diagnostic technology with high temporal and spatial resolution of 500 Hz and 5 k Hz were used to investigate the development process of volatiles combustion and the evolution process of volatiles ignition of single particle in pulverized coal particle stream. The time characteristics from ignition to volatiles combustion of pulverized coal particle stream were obtained through the combination of the two. The devolatilization and volatile combustion behavior of pulverized bituminous coal and lignite were investigated with OH-PLIF technology. The relative standard deviation of radial OH signal distribution was used to describe the flame stability. The stability of bituminous coal particle stream combustion is higher than that of lignite under the same combustion conditions. Based on OH-PLIF and CH*chemiluminescence diagnostic techniques,a dynamic mode decomposition method( DMD) was proposed to investigate the combustion oscillation characteristics of volatiles in pulverized coal particle stream.With increase of oxygen concentration,the oscillation of volatile flame is enhanced. The agglomeration of particles may lead to lower frequency oscillation for pulverized coal volatiles combustion. On the contrary,higher oscillation frequency will be produced by individual or separate particle combustion. However,the current achievements are not sufficient. So it is necessary to continue to carry out in-depth research on the optical diagnosis test of pulverized coal combustion,explore the generation and emission of NOxand the mechanism of water vapor in new water-oxygen combustion technology,and develop new clean coal combustion technology,so as to make further contribution to the clean and efficient utilization of Chinese coal resources.