The environmental conservation values of wetland plants were estimated in successive terms, by using the calculation model of ecosystem service values. The removal experiments of CODcr and TN in wastewater were carried out. Cattail, reed, small sedge and potamogeton were chosen as experimental wetland plants, while vertical flow wetland was constructed by using flyash concrete as filling material. The results show that the environmental protection function of wetland is remarkable. Of the whole ecosystem service values of the wetland plants, the most is the pollutant purification value accounting for 28.95%, while the least is the raw food production value accounting for 0.11%-0.48%. Cattail has the greatest purification capacity of CODcr in wastewater with the removal rate of 42.64%, potamogeton has the greatest purification capacity of TN with the removal rate of 62.83%, while reed has pretty good purification capacity of both CODcr and TN. The pollutant removal rates of the submerged plants increase with temperature rises.