Abstract: Aiming at the existence of uncertainties and complexities in the environmental-protection system operation processes of thermal power plants, based on environmental-protection tax and environmental-protection electricity-price mechanism using interval linear programming(ILP) and mixed-integer programming(MIP) methods, an inexact environmental-protection system operation optimization(IESOO) model was developed to achieve the stability and economy of environmental-protection facilities operation as well as pollutants control and pollutants emission reduction. The interval solutions were obtained, and solutions analysis indicated that based on the environmental-protection system operation parameters as well as pollutants emission standard and environmental air quality standard,through the comprehensive balance of the cost of pollutants treatment and emission, the appropriate pollutants treatment efficiencies were determined, then the reasonable economic cost of pollutants treatment and emission as well as system total cost were determined, so as to realize effective operation optimization control of environmental-protection system.