[Objective] To reveal the response of tree-ring width to hydroclimate factors, reconstruct long-term streamflow change by tree-ring width data in order to analyze its long-term change characteristics and finally provide scientific basis for water resource planning and management in Qingshui Basin at the southern slope of Tianshan mountains.[Methods] Pearson correlation analysis was used to reveal the correlation relationship between tree-ring width index and hydroclimate factors. The exponential transfer function was set up to reconstruct the runoff history of Qingshui River.[Results] In the common period, the positive correlation coefficients between tree-ring width index and precipitation from previous July to May of Baluntai meteorological station, and streamflow from previous August to July of Keerguti hydrological station were 0.579 and 0.641, respectively. Based on the exponential transfer function between tree-ring width index and streamflow, the annual streamflow from August in previous year to July of Keerguti station during 1639-2015 was reconstructed.[Conclusion] Tree-ring width showed its insufficiency to capture the extreme flood year. The low frequency characteristics revealed that there existed four drought periods and four flood periods in the past four hundred years. In the recent one hundred years, especially since 1950s, the frequency of extreme drought year was higher. The extreme drought years in this study showed good consistency with the drought events in the precipitation and hydrology series recorded by tree ring in the Tianshan Mountains area.