The micrometeorological characteristics of wheat, millet,soybean and paddy fields are analyzed utilizing the Bowen ratio-energy balance method. The results show that: 1)Albedo of wheat field decreases with wheat growth, which is 0. 25 at the enlongation stage, 0. 21 at the boot stage,and 0. 13 at the start of the ripening stage,respectively. Albedo of irrigated soybean field is 0.19 slightly lower than that (0.21) of non-irrigated soybean field. Albedo of millet and paddy fields is 0.21 and 0. 19 respectively. 2) Net radiation over the croplands depends mainly on latent heat flux in daytime,and it is mainly supplied by latent heat exchange at night. 3) Net radiation and its ratio to solar radiation increases with growth of crops.