中文摘要：

辽河中上游地区腹地是科尔沁沙地,河流径流是其重要补给源,研究径流及其变化原因对水资源合理开发利用、生态环境治理有重要的实践意义.以辽河中上游地区下洼、福山地、乌丹3个典型水文站点为基础,将气候变化归结为水热条件变化,通过改进的累积量斜率变化率比较法,定量分析径流变化、气候变化和人类活动对径流变化量的贡献.结果表明：径流量多年来呈减少趋势,随降水的增加而增加,随平均气温的升高而减少.径流量在2000年代最小,相对1990年代减少了45.89%-82.13%.径流突变点为1995年和1998年,1995-2010年（1999-2010年）与1957-1994年（1957-1998年）相比,下洼、福山地、乌丹站控制流域气候变化对径流减少的贡献率分别为41.57%、60.20%和36.76%,人类活动贡献率分别为58.43%、39.80%和63.24%.

英文摘要：

The Liaohe River is located in the middle and upper reaches and supplies the Khorchin sandy land. It is significant to study the runoff variation and its causes for water resources reasonable exploitation and eco-environment manage in the river basin. The climate change is attributed to hydro-thermal conditions change. The comparison way of cumulative slope change rate is improved,and runoff change,climate change and the contribution of human activities to runoff change are analyzed quantitatively based on the data from three typical hydrometric stations（ Xiaw a,Fushandi and Wudan） on the middle and upper reaches of the river. It is found that runoff has been decreased slow ly for many years,including some increase due to precipitation increasing and some decrease due to air temperature rising. In the 2000 s,runoff reached a minimum,45. 89% - 82. 13% of that in the 1990 s. 1995 and 1998 were the runoff abrupt change years. From 1995 to 2010（ 1999 to 2010） the climate change in the areas controlled by Xiaw a,Fushandi and Wudan hydrometric stations contributed 41. 57% 、60. 20% and 36. 76%,respectively,to the runoff decrease,and the human activities contributed 58. 43% 、39. 80% and 63. 24%,respectively,to the runoff decrease,as compared with that from 1957 to 1994（ 1957 to1998）.