It is sensitive to climate change that the boundary of the northwest monsoon region as the northern boundary of the Asian summer monsoon. Knowledge of natural drought variability and the mechanism is essential for the development for human society and economy,especially in arid and sub-arid regions. Here we present a new tree-ring chronology from Tulugou,in the eastern Qilian Mountains. The correlation analysis between the tree ring width and meteorological factor showed that tree growth response to the drought in the growing season. And we compared the chronology and the nearby drought reconstructions,and the results showed that persistently drought periods occurred in the 1920s - 1930s,1966,1974,1982,1990s and early 21st century. Multitaper method spectral analysis indicates the existence of significant peaks at 2~ 4 years,suggesting a possible connection with the El Nino-Southern Oscillation. The results of the study are agreement with those of Helan Mountains,Qilian Mountains,Xinglong Mountains and Guiqing Mountains,which indicate that these areas may be influenced by the same climatic factors.