Abstract：Security and reliability for choosing a disposal location of high-level nuclear waste have been discussed. Eastern Tarim Basin and Beishan area are compared by terms of some geological condition factors such as earthquake occurrence frequencies and block stability together with analysis of isotopic and hydrochemical parameters in the water samples. The results show that a high-conductivity and low-velocity layer of the earth¢s crust is detected in the Beishan area，with the depth of more than 30 km. The basal lamina here is instable，accompanying major earthquakes frequently occurred in the past. Researches show that groundwater in Beishan area is neither sourced from “palaeo-water”nor from local precipitation，but from the precipitation in Qilian Mountain through large deep fault zones. Artesian wells with the volumes of 106 m3 per year are found in Huahai area nearby the Beishan area. Moreover，deep groundwater in this region belongs to fresh water. Runoff velocity is fast. If Beishan area was chosen as the disposal location of high-level nuclear waste，ecological environment of the lower reach，namely，Ejina Basin，would be destroyed. In contrast，eastern Tarim Basin belongs to stable block. High-conductivity and low-velocity layers are not found in this area. Major earthquakes did not occur in geological period. Groundwater originates from infiltrated supply of rivers and lakes，with the total dissolved solids(TDS) values increase with depth. The circulation period of the groundwater is relative a long time. The runoff underneath eventually flows to the Lop Nur gobi area. In addition，there covers granite with the area larger than 3 000 km2 underneath the earth surface of military base in eastern Tarim Basin. As a result，it seems to be more secure and reliable if choosing the polluted nuclear tests base station in eastern Tarim Basin as permanent disposal location than Beishan area. The destroy degree to ecological environment could be dropped to lowness if the disadvantageous events happen in the future.
