Abstract: The large aperture scintillometer (LAS) is a device that measures the turbulent intensity of the refraction index of air.The instrument consists of a transmitter and a receiver, which are placed at a given distance apart with the path length being to 5 km.Therefore, the measurement of LAS is an area-averaged result between the transmitter and the receiver.At the receiver the spatial turbulent intensity is expressed in the refractive structure index C_n². With some additional data users are able to derive the sensible heat fluxes between surface and atmosphere.As part of the Chinese-Dutch CEWBMS (China Energy and Water Balance Monitoring System) project, five LASs were installed in China.As one site representing the agricultural area in North China, a LAS was set up over a crop field at Zhengzhou in Henan Province with a path length of 1350 m.Using the LAS measurements and some additional data collected in the Zhengzhou site in 2000, daily average sensible heat fluxes are deduced, and the basic characteristics of surface energy balance components during the w hole year are analyzed.The results show a good consistence with the features of the rainfall and the soil relative humidity in the same period.This work improved the understanding of the seasonal variation of the energy balance in the LAS site area; furthermore, provided the phy sical foundation for the LAS application in local surface energy balance monitoring.