建立有效的政府间横向合作机制是完善我国跨界水环境管理的重要途径。我国已经在国际跨界水域共管、国家层面上的部际合作、地方政府间的跨界水域合作以及地方政府内部部门间的合作等方面做了大量的尝试并取得了理想的效果。目前，我国各类政府间横向合作主要是通过协议、计划、联合行动、联席会议等方式开展，而且一般都有政府部门的参与。合作的内容从法律、政策、机构到信息共享与监测和评价，非常广泛。由于尚存在着法律、协调机制、科技支撑等方面的一些问题，我国政府间横向合作机制还远未发挥出应有的作用，总体上跨界地表水污染仍然较严重。为此，必须采取完善机制的体系、完善机制的结构、深化机制的核心内容、丰富机制的实现方式、健全机制的保障条件等对策。

Development of an effective inter-governmental horizontal cooperative mechanism is an important solution to improve the trans-boundary water environment management in China. Much efforts has been performed and desired results have been achieved in the international trans-boundary water co-management, cooperation among different ministries in China, trans-boundary water cooperation among local governments, and departmental cooperation inside one government. At present, the horizontal cooperation among governments is carried out through the agreements, planning, joint action, and joint conference, and these methods generally involve different departments of the government. The content of the cooperation includes the law, policy, institution, and information sharing, monitoring and assessment. However, due to the existing problems in the law, cooperative mechanism, and technical support, the inter-governmental horizontal cooperative mechanism did not act significantly effectively in China and the contamination in trans-boundary surface water is still severe. Therefore, several countermeasures were proposed in this paper, including the improvement of system and structure of the cooperative mechanism, strengthening of the core content of cooperative mechanism, enrichment of realization solutions of cooperative mechanism, and improvement of the secure conditions of cooperative mechanism.