Mainland China has 2538 nature reserves, covering approximately 15% of its total land area. However, little is known of their effectiveness in capturing the country's ecological diversity. We calculated the degree of representation of terrestrial ecoregions, biodiversity priority areas, and vegetation types within 2217 of these reserves for which spatial data were available. Of the total area set aside as nature reserves, almost 56% was concentrated in the three western provinces of Tibet, Qinghai, and Xinjiang. Of the 53 ecoregions found in China, 29 had over 10% of their land protected through the reserve system; in addition, most (81%) of China's natural vegetation communities were represented in at least one nature reserve. On the basis of these findings, we recommend that China should (1) conduct a nationwide ecoregional biodiversity assessment; (2) establish a georeferenced (spatially referenced) database of nature reserves and other types of protected areas; (3) increase efforts to improve international cooperation regarding management of cross-border ecoregions; and (4) create or expand reserves in eastern and southern China, with a focus on protecting ecosystem services to help sustain local communities' economies.