中文摘要：

利用主成分回归分析法，选取石羊河流域的5个影响因素进行定量分析，得到3个主成分，其累计方差贡献率达92．786％．根据3个主成分各自对应的特征向量特点，分别解释为人为因子、温度因子和降水因子并进行回归分析．根据回归方程，近50a来人为因子在水资源变化过程中起主导负作用，其影响力占总影响力的-58．48％，大大超过了降水因子22．35％的正作用；而温度因子虽其影响力不是很大，只占总影响力的-19．17％，却加剧了水资源进一步减少的趋势．

英文摘要：

Shiyang River Basin is a typical fragile zone of water resources in arid regions. Long-term natural evolution and human activities have seriously destroyed the balance of the water cyclic system of this region. By use of the principal component regression analysis, 5 influencing factors were quantitatively analyzed, and 3 principal components with the accumulative variance contribution rate 92.786% were obtained. According to the corresponding eigenvectors, the 3 principal components were explained as the anthropogenic factor, the temperature factor, and the precipitation factor. The regression analysis shows that the anthropngenic factor plays a leading negative role in water resources variation in recent 50 years, and its effect accounts for - 58.48% of the total effect, which is much greater than the positive effect of the precipitation factor with the effect accounting for 22.35%. It is also demonstrated that, although the effect of the temperature factor only accounts for - 19.17%, it accelerates the decrease of water resources.