A knowledge based geneticsimulatedannealing method for optimizing the tube circuit of finandtube heat exchangers was presented by introducing specialized knowledge and the simulated annealing method into the existing method.Case studies were performed on a practical finandtube heat exchangerThe optimization target is to obtain maximum heat exchange capacity of the heat exchanger with the constraint conditions of practical manufactureThe test results showed that after optimization;all paths of the optimal tube circuit were uniformly distributed in the airflow field and contained equal number of tubes;and the imbalance of heat transfer among the paths was avoidedThe heat exchange capacity of the heat exchanger was 22% larger than that before optimization;and was 103% larger than that obtained by the existing puregeneticalgorithmbased optimization method.