This study examines the association between carbon emission levels or carbon emission levels of unit cost (ton per thousand dollars) and firm performance in Taiwan. The empirical results show that carbon emission levels and carbon emission levels of unit cost are negatively related to firm performance; especially, the relationship between carbon emission levels and firm performance is more negative for the firms adopting green investment strategy than the firms without adopting green investment strategy. The results of this study suggest low carbon emission levels and low carbon emission levels of unit cost can improve firm performance.