Abstract: Eddy-Covariance method has been widely used in the research of mass transport(such as CO₂ and H₂O) and energy exchange between the terrestrial ecosystem and the atmosphere in recent years,and how to evaluate the reliability of eddy-covariance observational data becomes very important.In this paper,the characteristics of energy budget and radiation balance are analyzed,and the relationship of turbulent fluxes(sensible heat flux plus latent heat flux) and available energy(net radiation minus surface soil heat flux) are studied through OLS linear regression and EBR methods,by using the observational data in the cropland surface at Wenjiang site in Chengdu Plain from January to December,2008.Some significant results are obtained.