综合已有的生态学数据和知识，对生态系统进行科学的评估，以确保对生态系统的保护和合理利用，是人类福利及其可持续发展的重要保障。结合国际上“千年生态系统评估”计划的最新成果，对生态系统评估的概念和内涵进行了详细的阐述。生态系统及其服务功能与人类福利之间的联系是生态系统评估的核心，因此，生态系统评估的概念框架主要包括：生态系统及其服务功能、人类福利与消除贫困、生态系统及其服务功能变化的驱动力、生态系统不同尺度间的相互作用和评估，以及生态系统的价值与评价等基本概念。对以上基本概念和内涵及它们之间的相互关系的准确理解和把握是开展生态系统评估的前提条件。当前，在生态系统及其服务功能评估的综合性、驱动力分析和评估尺度的选定等方面尚面临挑战，仍需进行深入探讨。

Bringing the data and new findings in ecology to bear on ecosystems assessment, which can contribute to the protection and reasonable use, and can make human wellbeing progress toward sustainable development. Based on the first product of “Millennium Ecosystem Assessment”, this paper has presented main concepts and its implications of ecosystem assessment in detail. Because the emphasis of ecosystem assessment is to study the relationship between ecosystem services and human wellbeing, the main concepts of ecosystem assessment expounded in this paper include ecosystem and its services, human wellbeing and poverty reduction, drivers of ecosystem change, crossscale interaction and assessment of ecosystems, and values associated with ecosystem. Successful ecosystem assessment is vitally dependent upon the understanding of the above concepts. Presently, we are facing challenges on carrying on integrated assessment of ecosystem services，driving force analysis, and scaling issues.