Cost-benefit analysis is a significant method in environmental policy evaluation and technological feasibility assessment,it analyzes the total cost and total benefit of proposed environmental policy from aspects of environment,economics,health,social,etc.,in order to select the best policy or technological proposal.The article introduces international advanced cost-benefit analysis methods and models,and adjusts them in accordance with practice in China,then analyzes the Mercury Reduction Plan in national “12th Five-year Plan”.The result shows that,with the discount rate of 7%,the annual benefit of the Mercury Reduction Plans execution is nearly 88.79 billion RMB,and the annual cost is nearly 10.04 billion RMB; with the discount rate of 3%,the annual benefit of the Mercury Reduction Plans execution is nearly 100.38 billion RMB,and the annual execution cost is 29.75 billion.In conclusion,the national “12th Five-year Plan” is accordance with the coordinated develop principle of social,economic and human health.