Does firms' carbon reduction only comply with global trends or it can further add value to firms? This study examines the relationship among top managers’ cash bonus, carbon reduction, such as carbon emissions reduction and carbon intensity reduction, and firm value in Taiwan. The empirical results are robust after controlling for firm size, sales growth rate, debt rate, R&D ratio et al. They show the relationship between carbon intensity reduction and firm value is significantly positive. In contrast, the relationship between carbon emissions reduction and firm value is negative. The results also support the contention that top managers’ cash bonus has significant moderating effect on the positive relationship between firm value and carbon intensity reduction and the negative relationship between firm value and carbon emissions reduction. The moderating effect of top managers’ cash bonus on the relationship between firm value and carbon intensity reduction is more positive for firms in the high carbon industries than those in other industries.