The invention provides a flue gas denitration system aided design system. The flue gas denitration system aided design system can automatically calculate design parameters of the flue gas denitration system according to input data, so as to provide reference for the design of the flue gas denitration system, save calculation amount, lower calculation difficulty and improve calculation accuracy rate and design efficiency. The flue gas denitration system aided system comprises a data input module used for inputting data, a calculation module used for receiving the data input by the data input module and finishing the design of the flue gas denitration system, a data output module used for receiving the calculation result of the calculation module and outputting the calculated result, and an equipment aided design module.