Abstract: To improve the overall performance of an organic Rankine cycle, a multi-objective optimization model was established from the perspectives of thermoeconomics and exergoeconomics by taking the total investment per unit power output and the cost per unit exergy of the system as the performance indicators. For the 423.15 K low temperature flue gas waste heat source, the R245fa, R123, R114, R245ca, R601, cyclohexane, butane, and R236ea were chosen as the candidate working fluids. The model established was solved using the multi-objective gray wolf algorithm (MOGWO), while the effects of evaporation temperature and condensation temperature on the turbine efficiency were analyzed with a one-dimensional radial-inflow turbine efficiency prediction model. Results show that, for all the working fluids, the turbine efficiency reduces with the rise of evaporation temperature, but increases with the rise of condensation temperature. Among the working mediums selected, R601 is the optimal working fluid.