Abstract: Research has found that a fin structure combining longitudinal curved corrugations with vortex generators in a tube-fin heat exchanger can enhance the heat transfer performance of circular tube fin heat exchangers. The impact of amplitude of the curved longitudinal corrugation on fluid flow and heat transfer performance of a heat exchanger is investigated numerically. The vorticity field, heat transfer, resistance, and overall heat transfer performance are analyzed for different amplitudes. The results show that the intensity of longitudinal vortices gradually increases as the increase of amplitude. The fluid's scouring effect on the wall also intensifies with the increase of vortices, which effectively disrupts the thermal boundary layer and significantly improves the heat transfer performance of the exchanger. In the range of Re=200~1 000, compared with the plane fin and the straight corrugation fin, the maximum Nu for the longitudinal corrugated fin increases by 72.7% and 14.5%, respectively, while the friction factor f increases by 161.8% and 44.8%, respectively. The thermal performance factor JF for the curved corrugation can reach a maximum of 1.268, a 26.8% improvement over the plane fin. Correlations for Nu, f, and JF with deviations less than ±3%, ±10%, and ±6%, respectively, are fitted to facilitate their application in engineering.