Abstract: To accurately evaluate the hydrologic drought, it is necessary to objectively construct the drought index. In this study, the data collected from two hydrologic stations in the upper reaches of Fenhe River basin were used as case studies. Firstly, the ability of the logistic, normal, two-parameter log-normal, and Weibull probability distributions was examined to choose the most suitable distribution function for establishing the standardized streamflow drought index (SSDI). Secondly, the hydrologic drought magnitudes were divided based on the characteristics of standard normal curve. Finally, the SSDI was compared with the Z index and departure index of streamflow. The typical records of drought and flood events in the Fenhe River basin were taken as evaluation standard, which was used to evaluate the applicability and rationality of the SSDI and drought magnitudes. The results showed that, the two-parameter log-normal distribution was selected as the best fitting function for monthly streamflow in the study area. The SSDI and the magnitudes were both coincident for the actual drought-flood severity. In addition, the occurrence of various hydrologic drought magnitudes was stable at various time scales. The conclusion could provide scientific basis of drought defense, disaster mitigation, and water supply planning measures for the upper reaches of Fenhe River basin.