Abstract: The well-known biomass material, cellulosic bioenergy grasses such as switchgrass (Panicum virgatum), silverreed (Triarrhena sacchariflora) and giantreed (Arundo donax), are important bioenergy plant resources with great development potential. In this research, the evaluation of economic benefits and ecological values was employed in the entire process from the farming culture of cellulosic bioenergy grasses to the production of cellulosic ethanol. During the production of cellulosic ethanol from the biomass of these grasses, the economic benefits were 4 147.85, 1 185.08 and 2 019.76 yuan RMB per tonne cellulosic ethanol for the three grasses respectively, and from an economic point of view, switchgrass is economically optimal, followed by giantreed, and then silverreed. The ecological value of air purification was 4 639.28, 4 351.25 and 4 320.39 yuan RMB per tonne, respectively, and from an ecological point of view, switchgrass is ecologically optimal, followed by silverreed, and then giantreed. The potential for CO₂ fixation of switchgrass, silverreed and giantreed are huge and have a positive effect on the reduction of CO₂ concentration, greenhouse gasses, and the accumulation of soil carbon.