Abstract: Based on the error comparison and analysis of the estimation methods of the river period fluxes,the contributions of the time-averaged dispersion fluxes to the measured period fluxes of river cross sections are discussed.The influences of pollutant source types,which could be classified as point sources and non-point sources,on the selection of fluxes estimation methods are also discussed.And according to two examples,the applicability of fluxes estimation methods and the principle of selection are analyzed.