Abstract: The value system of constructed wetland is presented, which consists of environmental-economic values and cost values, and the environmental-economic values are composed of environmental capacity value, resource value and social value while the cost values composed of maintenance value and man-made reconstructed value. The contingent valuation method is introduced to study the procedure and method of assessing the environmental-economic values for constructed wetlands. Finally, a case study from Maguanqiao constructed wetland in Shenyang City is conducted through questionnaire and mathematic statistics, and the calculating results show that its total value is about RMB 157.897 million yuan, its total economic profit about RMB 82.273 million yuan, along with the cost-benefit ratio of 1∶6.3, and its environmental and economic benefit is greatly prominent.