The heat flux、latent heat flux and CO2 flux of winter-wheat on Daxing station were measured by eddy correlation technique.Then analysis the characteristics and the relationship between heat and carbon flux and the variation of water use efficiency of winter filed during wheat heading stage.Main findings are as follows: Firstly,the curve of CO2 flux in diurnal course is single vale,and the extremum value appeared about 12:00 am,the shape of heat and latent heat flux is single kurtosis;Secondly,in the heading...