The heat exchanger model of air-condition is deal with the reasonable simplification and in order to take numerical simulation about heat exchange in air side, the Fluent is adopt. Optimized design include four aspects: fin thickness, fin height, distance between two fins and the shape of ripple fins. After the numerical simulation, the best structural parameters of fin are received. It can provide a theoretical basis for design and research. After this optimized design, the exchanger can improve the heat transfer ability and save many materials.