Abstract: Based on the 1951〖KG-*2〗-〖KG-*7〗2007 observation data of precipitation and temperature from To ngliao, Kailu, and Zhalute meteorological stations as well as the related hydrol ogic data from Tongliao hydrological survey bureau and water affairs bureau, the change characteristics of the climate and water resources in west Liaohe River Plain were studied. The results showed that in 1951〖KG-*2〗-〖KG-*7〗2007, the precipitation in its periodical changes in study area had a decreasing trend. Th e tendency rate of precipitation was -132 mm·（10 a）-1, and the instability of precipitation was increased. The runoff of four inbound rivers including Xil amulun all decreased, with the mean annual runoff in 2001〖KG-*2〗-〖KG-*7〗2007 being only 228% of that in 1990〖KG-*2〗-〖KG-*7〗1994. From 1951 to 2007, th e runoff of west Liaohe River decreased, and the days of its zero flow increased . Since 2001, the River had been zero flow. The groundwater overdraft area and t he funnel area in Keerqin Region in 2006 increased by 85 times and 15.5 times, respectively, compared with those in 1978; and the average groundwater level in Keerqin Region, Kailu County, and Naiman Banner in 2006 increased by 376 m, 2 77 m, and 193 m, respectively, compared with that in 1980. Since the 1970s, the number of electromechanical well in study area was increasing, irrigation amount had a fluctuated rise, and the proportion of agricultural water consumption had different extent decrease. Therefore, to exploit and use the water resources in atmosphere, to popularize water-saving irrigation technologies, and to make a reasonable arrangement of industrial structure were the effective measures in re alizing the sustainable utilization of water resources in west Liaohe River Plai n.

Key words: stable carbon isotope, dissolved inorganic carbon (DIC), partial pressure of CO₂(pCO₂), Wanfenghu Reservoir, karst area.