Different from the traditional way of measuring evaporation of water surface,which is based on static water balance,a new way of measuring evaporation of water surface was brought forward,which was considered in technical innovation and was based on dynamic water balance.The practical application was introduced.The advantages of new way include:(1)actualized automatization of measuring evaporation of water surface;(2)founded dynamic measuring way,which was distinguished from traditional way by measuring water surface variation,and water surface was invariable during measuring;(3)sampling interval could be changed by person in the measuring way and the way accurately measured the diurnal variation of evaporation of water surface and its measurement precision was0.0015mm/h.