The invention provides an optimization method for determining a 
flue gas 
excess heat organic Rankine cycle system parameter. The optimization method comprises the steps of taking into account of a cooling 
water cycle to establish a 
thermodynamic model; through a first law of 
thermodynamics and a 
second law of thermodynamics, obtaining 
system net output power, water pump waste power, heat efficiency, (the formula is shown in the description) efficiency and 
irreversible loss, and according to the influence of an 
evaporation temperature and an 
expansion ratio on 
system thermodynamic performance, determining an optimal 
evaporation temperature; under the optimal 
evaporation temperature, calculating heat exchange areas of an 
evaporator and a condenser, wherein it is defined that an economical objective function is the ratio of the system net output power to the area of the 
evaporator to the area of the condenser, and the comprehensively 
evaluation function is the weighted sum the economical objective function (the formula is shown in the description) and the efficiency; with the comprehensive 
evaluation function being an optimization target, determining an optimal 
condensation temperature; according to the optimal 
evaporation temperature and the optimal 
condensation temperature, determining 
system parameters of work medium 
mass, cooling 
water mass, evaporation pressure, condensation pressure, an 
expansion ratio, the net output power, the heat efficiency and the 
irreversible loss. According to the optimization method for determining the 
flue gas 
excess heat organic Rankine cycle system parameter, the optimal 
evaporation temperature and the 
condensation temperature can be determined, and thus the optimal system parameter is determined.