Abstract: This paper gives the measurements of the sensible heat flux over saline-alkali land by LAS (L arge Aperture Scintillometer) in the growing season of 2000.Calculations of water-heat balance have been made.In Qianan saline-alkali land area,the sensible heat flux accounting for netradiation is 65% in drought and non-growing seasons,11% in rainy and grow ing seasons.The sensible heat flux decreases obviously due to rainf all,the decrease is related to the rainf all rate.And this aspect canindicate the character of the soil.Comparing with the tranditional gradient method,the two sets of data are consistent.