Water surface evaporation is an important element of hydrological monitoring.At present， artificial observation is still an important means of water surface evaporation observation，and there are many factors affecting water surface evaporation observation.The current“water surface evaporation observation specification”（SL630-2013）stipulates the source and control of water surface evaporation observation error，but the scope of each error is not clearly specified.In order to provide a basis for evaluating the reliability of water surface evaporation data，the error of manual observation and estimation of E601 standard water surface evaporator is analyzed.The experimental analysis shows that the wind power and the water surface evaporation observation uncertainty are positively correlated for the greater the wind force and the greater the observation uncertainty.After field practice and analysis，this paper puts forward supplementary suggestions on the links not involved in the manual observation operation requirements in the“water surface evaporation observation specification”（sl630-2013），providing reference for improving the quality of artificial observation of water surface evaporation