Abstract: Ammonia, as a hydrogen containing fuel with great potential for application, has received widespread attention. Real time measurement of its combustion temperature field and nitrogen oxide concentration field of combustion products plays an important role in understanding the mechanism of ammonia combustion and controlling the amount of ammonia injection in denitrification processes. This paper combines the advantages of spontaneous emission signals and laser absorption signals in measuring the combustion temperature field and medium concentration field, respectively, to conduct research on the measurement of ammonia combustion temperature field and NO concentration field. A combustion model for a flat flame burner is established and the combustion of ammonia mixed with hydrogen is simulated. Under different blending ratios, the combustion temperature field and water vapor concentration field have similar distributions. The highest temperature decreases with the increase of hydrogen blending ratio, and the main nitrogen oxide produced by combustion is NO. The concentration of NO increases with the increase of hydrogen blending ratio. The simulation results are used as the original temperature field and concentration field, and the integrated narrow band ratio (ISBR) method is used to reconstruct the temperature field and water vapor concentration field of ammonia hydrogen combustion under different measurement errors. When the measurement error is 1%, the reconstruction error of the temperature field for ammonia hydrogen 30% is 0.53%, and the reconstruction error of the H2O concentration field is 2.81%. Finally, combined with tunable diode laser absorption spectroscopy (TDLAS) technology, the concentration field of NO is reconstructed by selecting suitable absorption lines, and the reconstruction accuracy under different optical paths is discussed. The results show that with a measurement error of 1%, the reconstruction error was 2.39% when 10 optical paths were arranged, and 5.42% when 4 optical paths were arranged. In practical applications, the appropriate number of optical paths can be arranged according to the accuracy requirements to reduce the complexity of the measurement system.