千年生态系统评估（MA）是由联合国秘书长安南于2001年6月宣布启动的一项为期4年（2001—2005年）的国际合作项目，这是在全球范围内第一个针对生态系统及其服务与人类福祉之间的联系，通过整合各种资源，对各类生态系统进行全面、综合评估的重大项目。依据MA发布的最新成果，主要从3个方面介绍了它的重要成就与贡献：①首次在全球尺度上系统、全面、多尺度地揭示了各类生态系统的现状和变化趋势、未来变化的情景和应采取的对策，其评估结果为改善与生态系统有关的决策制定过程提供了充分的科学依据；②丰富了生态学的内涵，明确提出了生态系统的状况和变化与人类福祉之间的密切联系，将研究“生态系统与人类福祉”作为现阶段生态学研究的核心内容和引领21世纪生态学发展的新方向，从而将生态学的发展推进到了一个新的阶段；③ 阐述了评估生态系统与人类福祉之间相互关系的框架，并建立了多尺度、综合评估它们各个组分之间相互关系的方法。MA的实施虽然取得了巨大成就，但是它所提出的一系列理念、方法和数据仍需不断完善。这些问题的解决，尚需有关学者今后进行长期不懈的努力。

Millennium ecosystem assessment（MA）was launched by United Nations Secretary-General Kofi Annan in June 2001 and was completed in March 2005. So far, the MA is the first international work program designed to assess the global ecosystem by synthesizing information from all kinds of sources. The assessment focuses on the linkages between ecosystems and human well-being and, in particular, on "ecosystem services". Based on the latest findings, three main contributions presented by the MA were expounded in this paper. ① Conducted a comprehensive global assessment of the world’s major ecosystems and its four main findings, which can provide substantial scientific basis for decision-makers to improve their decision-making processes concerning ecosystem management; ② Enriched the connotation of ecological research by pointing out explicitly that a change in ecosystems is closely related to human well-being, and placing the study of “ecosystem and human well-being” as one central task for current ecologists, which can lead the development of ecology in 21^st century; ③Established a framework to assess the interactions between ecosystems and human well-being, and a analytical approach to conduct multi-scale and integrated assessments. Though great achievements have been gained with the MA implementation, but many issues still need to be discussed or improved, including concepts, methods and data.