In order to ident ify the water resources security and investigate the way for sustainable development of water resources, a new concept of water resources carrying capac-ity (WRCC) has been widely studied in the regional sustainable development during the past decades. Asacase study, the methods of WRCC has been invest igated for Zhangy eregion, located in the middle Heihe river basin. Adynamic and integ rated model of WRCC waterr esources carrying capaeity is established in the frame of mult-icriteria analysis on the basis of the major sectoral models including the extended input-out model, the assessment model of virtual water and the comprehensive evaluation model of WRCC, which provide an integrated frame for the study of water resources development, land use, virtual watert rade and so cio-economic development. The WRCC in different scenarios is discussed and the influence of some important policy factors on WRCC is evaluated including the adjustment of industrial factor, improvement of water-saving technology, implementation of "water allocation" scheme, virtual water strategy, etc. The study indicated that the WRCC of Zhangye still has considerable potent ialities for sustaining the economic development with an annual rate of about 7% of GDP grow th and the natural growth of the population at "Comparatively Well off" living standard of the main agricultural products in 20 years premised with the implementation of "wateral location" scheme and the necessary environmental protection.