A CO_2-capture process for the flue gas from electric power plants is modeled by the simulation tool Aspen plus in this paper. The DEA is used as chemical absorption for CO_2-capture. And then the effects of the critical parameters to the system performance are analyzed. At last, three models are built by MATLAB to evaluate the environmental impact of CCS (carbon capture sequestration) technology. The results show that the higher temperature of the solution could reduce the DEA loss and the reboiler heat duty. However, raising the temperature of the solution will lead to additional energy consumption. The reboiler heat duty becomes the lowest when the mass fraction of DEA (diethanolamine) of the solution is 0.25. When the leakage factor of the ship transport scenario is 0.05, the effective emission factor of the plant is higher than that of the reference plant, and then the CCS technology will not play a role in the mitigation of the climate warming.