Based on four types of ecosystem services, including provisioning services, regulating services, cultural services, and supporting services, changes in global ecosystem services during the second half of the twentieth century were assessed in the report of MA's condition and trends working group. It indicated that approximately 60% (15 out of 24) of the ecosystem services evaluated in the MA are being degraded or used unsustainably, 18% (4 out of 24) are being enhanced, and 22% (5 out of 24) are being used with mixed patterns. The most important changes of ecosystem services include:① The supply of certain ecosystem services has increased at the expense of others. Significant gains in the provision of food and fiber have been achieved through habitat conversion, increased abstraction and degradation of inland waters, and reduced biodiversity; ② Fish cannot continue to be harvested from wild populations at the present rate. Deep-ocean and coastal fish stocks have changed substantially in most parts of the world and the harvests have begun to decline and will continue to do so; ③ The supply of fresh water to people is already inadequate to meet human and ecosystem needs in large areas of the world, and the gap between supply and demand will continue to widen if current patterns of water use will continue; ④ Declining trends in the capacity of ecosystems to render pollutants harmless, keep nutrient levels in balance, give protection from natural disasters, and control the outbreaks of pests, diseases, and invasive organisms are apparent in many places; ⑤ Supporting services, which are necessary for the production of all other ecosystem services, have changed with mixed patterns.