The tree ring structure and time series variation of Ulmus pumila var.sabulosa in the Otindag Sand Land were researched based on the theory and technology of dendrochronology.The responses of the basic statistical results,such as the sensitivity and signal-to-noise ratio of tree ring width,earlywood width and latewood width chronologies,were analyzed.The purposes of this study were to provide the basis for reconstructing the paleoclimate in the Otindag Sand Land.The results were that there was a significant boundary between earlywood and latewood, because elm has a typical ring porous wood structure.The trends of time series variation of ring width,earlywood width and latewood width were consistent,especially the correlation between latewood width and tree ring width was as high as 0.98 (P < 0.001) .Mean sensitivity,signal-to-noise ratio and expressing population signal of latewood width and tree ring width were higher than those of earlywood width.The compared results revealed that RES was more suitable to be used to analyze tree ring width and climate change.