Abstract: In the field observation experiment of land surface process, the eddy covariance technique can directly measure the water vapor and heat fluxes between ground and atmosphere, which has become a widely used technique and method in the world. However, the surface observation conditions are difficult to meet the theoretically requirements, and the observation deviation will have an impact on the surface energy balance and land surface simulation. Flux data quality is not only the basis for the feasibility of long-term field observation experiments, but also high-quality flux data from different surface environments has a certain significance for the study of global climate change response. This paper summarized the application results of the eddy covariance technique, the influence of data processing on the flux and the applicable selection of different correction methods in the underlying surface, applying the data preprocessing, coordinate rotation correction, frequency response correction, sonic temperature correction and air density correction. On the basis of discussing the deficiency of flux data processing method of eddy covariance technique, the future research is discussed.