Non-methane hydrocarbon (NMHC) emission from plants significantly affects the atmospheric environment change. Isoprene is the main NMHC in the troposphere. With the light-temperature model put forward by Guenther, isoprene emission from Chinese forest ecosystem was estimated. The result showed that the total isoprene emission was 0.03-8.6 Tg/a and release 0.026-7.589 TgC/a, which is 1.5%-4.3% of the global one. Isoprene emission has largely spatial variation, and the higher emissions occur in Southern and Northeast parts of China, where large forests are distributed. Yunnan and Heilongjiang are two higher emission provinces of China, and their contributions to the total are about 22% and 11%. The contribution varied with different species. The emissions from poplar and oak forests contribute 52.28% and 44.29% of the total, respectively.