Based on the likelihood ratio method testing in the mean and the Schwarz Information Criterion testing in the variance

the variability of nonuniform coefficients of annual streamflow distribution in the gauging runoff series and reconstructed runoff series returning water regulation of three large reservoirs in the Dongjiang River is analyzed in this paper. Main conclusions are as follows：Compared to reconstructed series

annual mean values of the nonuniform coefficient of gauging series significantly decrease

being between 0.47-0.63

while annual variation coefficients remarkably increase

being between 0.34-0.48. The changepoint of the nonuniform coefficients obviously occurred in 1968. Both annual mean values and variation coefficients decrease distinctly after the change point

with values between 0.40-0.54 and between 0.25-0.32 respectively. The segmentation point of the nonuniform coefficient of reconstructed series also occurred in 1968 regardless of no tested change point. Annual mean values after the segmentation point show little change

but annual variation coefficients greatly decrease. The variability of the nonuniform coefficients in annual streamflow distribution is mainly resulted from water regulation of three reservoirs in the Donjiang River.Some other factors influence the annual variation range.