研發扣抵政策之有效性在過去文獻有著不一致的結果，許多研究者認為可能原因之一即為與兩稅合一的衝突，實施兩稅合一之後，在有限的資金之下將增加公司發放股利的誘因；同樣的，在實施研發扣抵後亦將增加公司研發投資的金額，都會影響彼此的政策效果。 　　近年來台灣經歷獎勵投資條例、促進產業升級條例及現在的產業創新條例，其對投資之效果飽受爭論。而我國除採取研發扣抵政策外，亦實施兩稅合一政策以解決重複課稅之問題，因此在台灣兩稅合一與研發扣抵是否會互相衝突會是一項值得探討的議題。 　　本文以 1996 年至 2014 年台灣與 OECD上市公司的非均衡追蹤資料 (Unbalanced panel data) 來進行分析。實證結果指出，同時實施兩稅合一及研發扣抵的國家相較於其他樣本，其股利支付與研發投資之間的關係呈現更為顯著的負相關，代表當同時實施雙重扣抵制度，兩項支出之間的衝突性更為明顯。 　　本文另外也做了台灣與其他國家的比較，實證結果指出，台灣雖實施雙重扣抵制度，但其支出之間的關係，反而呈現較為顯著的正相關。可能的原因即為台灣之研發扣抵相較於兩稅合一，其誘因明顯為大，因此文末亦作了 difference in difference 的敏感度分析，但結果顯示不論是 1998 年兩稅合一或 2010 年產創條例實施後，研發投資與股利支付之間的關係並沒有顯著的改變。 / The effectiveness of R&D tax credit is inconsistent in past literature, and many researchers believe one possible reason is the impact of dividend imputation credit. After imputation credit, it will increase the company’s incentive to pay dividend. Also, after R&D tax credit, it will increase the payment of R&D investment. So both of the policy will affect the effect of each other. In recent years in Taiwan, we experienced Statute for the Encouragement of Investment, Statute for Upgrading Industry and current Statute for Industrial Innovation, and their effect on investment suffered controversy. In Taiwan, we have not only R&D tax credit, but also the implementation of dividend imputation to relieve the problem of double taxation, so it becomes an important issue. This paper examines the unbalanced panel data of Taiwan and OECD from 1996 to 2014. Empirical results indicate that in the context of both R&D tax credit and dividend imputation credit compared to the other sample, the negative correlation is more significant between the dividend payments and R&D investment. It means when we implement both credits, the payments of dividend and R&D conflict more. This paper also examines Taiwan with respect to OECD countries, and the empirical results indicate that although the implementation of both credits, the positive correlation is more significant between the two payments in Taiwan. One possible reason is that the R&D tax credit in Taiwan is obviously more attractive than the dividend imputation credit. Therefore, I also use the sensitive analysis of difference in difference to examine this problem. However, it shows that after the implementation of dividend imputation in 1998 or R&D tax credit of Statute for Upgrading Industry in 2010, the relationship of payments doesn’t differ obviously.