From analysis of the characteristics and problems of mountainous city-river ecosystem, the integrated environment construction system whose contents are water security, water environment, water landscapes, water culture and water economy is proposed, and the connotation of it is detailed introduced. In additional, an example of mountainous river ecosystem construction in Lishui city, Zhejiang Province was presented in this paper, which including the establishment of flood control, water drainage, water supply, water demand of river ecosystem and water quality security system, the constitution of water environment protection, the combined construction of water landscapes with water culture, and finally giving the economy development schemes. This illustration provides references of mountainous city-river ecosystem construction mode and technological supports for urban river system construction.