The purposes of this study are to investigate the effects of a 24-week functional training program on physical strength and the isokinetic muscular strength and provide basic data to help to improve performance abilities. Both the control and experiment groups were put to the pre-test based on the physical strength factors required in elite boxers(muscular strength, muscular endurance, flexibility) and professional physical strength measurements(muscular strength of knee joints) to conduct Levene’s test and ensure intergroup homogeneity. Two-way RM ANOVA was conducted to examine the application effects of a functional training program. SPSS 22.0 for Windows was used for statistical analysis. The findings were as follows: the functional training program and the common boxing club training program had significant effects on the experiment and control group, respectively, in terms of physical strength factor changes. The experiment group, to which the functional training program was applied, showed a greater improvement in measurements than the control group, to which the general boxing club training program was applied. Both the groups exhibited significant effects in professional physical strength measurements after the application of the functional training program, but the experiment group recorded a greater improvement in changes. These findings indicate that the functional training program based on the periodization principle not only improved the physical strength factors needed by high school boxers. Finally, the study proposed that the functional training program developed for boxers should expand to other sports games and be applied for a long period of time to help players achieve good results, prevent injuries, and maintain their best conditions. The findings of the study will hopefully serve as basic data as an important foundation to help players boost the national prestige by getting good results at all kinds of world competitions and contribute to South Korea taking one step closer to its goal of becoming a world sports power.