The pre-tax deduction for enterprises R&D expenses is an important tax incentive, encouraging and supporting the technological innovation of China's enterprises. Based on the brief review on the implementation situation of the pre-tax deduction policy for enterprises R&D expenses with the latest survey results, the main factors influencing the effectiveness of the policy are pointed out and analyzed, including the limited field of R&D pre-tax deduction, the collection difficulty of R&D expenses, the inadequacy of R&D project management, the narrowness of policy benefiting surface, and the regional imbalance of the policy implementation. Finally, some corresponding suggestions are put forward, a useful references for promoting the policy in-depth implementation is provided.