Abstract:The capacity of plain forestry purifying air purification, fixing carbon and releasing oxygen of forestry in 2001 and 2005 were measured by methods of opportunity cost, shadow price, etc. The results indicated that 1) the total values of air purification, carbon fixation and oxygen release in 2001 and 2005 were 1.46 ×1012 and 1.87 ×1012 Yuan respectively. In 2005, the values of air purification in the northeast zone, the Chinese north zone, the Chinese east zone, the central south zone, the southwest zone, the northwest zone of China were 2.57 ×1011, 2.97 ×1011, 5.29 ×1011, 3.17 ×1011, 3.16 ×1010 and 1.24 ×1011 Yuan respectively, while the values of carbon fixation and oxygen release were 9.06 × 1010, 4.26 ×1010, 8.38 ×1010, 6.65 ×1010, 5.20 ×109 and 2.87 ×1010 Yuan respectively. 2) The descending order by the total values was sorted as: the Chinese east zone, the central south zone, the northeast zone, the Chinese north zone, the northwest zone, and the southwest zone. Based on such tremendous values, construction and management of plain forestry in China should be advocated to solve the problem of air pollution and increase forestry carbon sinks of plain areas in China.