OBJECTIVE：To stu dy the effects of R&D expense additional deduction policy on R&D investment and profitability of pharmaceutical manufacturing industry ， and to provide reference for improving R&D investment and profitability of pharmaceutical manufacturing industry. METHODS ：Based on the data of Chinese pharmaceutical listed enterprises during 2012-2019，regression discontinuity design and descriptive method were adopted to analyze the effect of R&D expenses additional deduction policy on R&D investment and profitability of pharmaceutical manufacturing industry. RESULTS ：Both R&D investment and the main business profit margin had significant “jump”at the policy cutoff point ，and the policy effect coefficient of the R&D expenses additional deduction policy on R&D investment and profitability of the pharmaceutical manufacturing industry were 0.310 and －1.197 respectively（P＜0.001）. The policy effect coefficient of the policy on R&D investment in the eastern region was 0.413（P＜0.001），while the effect on central and western regions were not significant ；the policy effect coefficient of the policy on R&D investment of large-scale and small- and medium-scale pharmaceutical manufacturing industry were 0.502 and 0.264 respectively（P＜0.001）. CONCLUSIONS ：On the whole ，R&D expenses additional deduction policy has a positive incentive impact on R&D investment of pharmaceutical manufacturing industry ，but does not have a positive incentive impact on the profitability which is greatly affected by other factors. The policy has regional differences in the incentive impact on R&D investment of pharmaceutical manufacturing industry ；the incentive impact of the policy on the R&D investment of large-scale pharmaceutical manufacturing industry is better than that of small-and medium-scale one. It is recommended to improve the R&D expenses additional deduction policy ，reasonably increase the profit margin of the pharmaceutical manufacturing industry ，adjust the policy for different regions and focus on guiding policies to favor small- and medium-scale pharmaceutical manufacturing industry，so as to improve the R&D investment and profitability of pharmaceutical manufacturing industry.