The present study is aimed at optimization of the geometers of the fin-and-tube heat exchanger with louver fin through numerical simulation. The optimization is carried out by using the simplified conjugate-gradient method (SCGM) is adopted for solving the optimal problem. Using the optimizer, the louver angle of louvered fin is adjusted toward the maximization of the performance of the heat exchanger. It is also shown that the maximum of area reduction ratios at the louver fin for Re Lp 100 - 400 with Lp = 1 mm. For the louver pitches, the following correlations for the optimal louver angle are derived, based on Reynolds number Re Lp ranging from 100 to 400. The results indicate the optimal louver angle applied in heat exchangers can effectively enhance the heat transfer performance. Thus, the correlations is derived that can be applied to the design of heat exchangers.