Objective：To study the treatment effect of one-visit root canal therapy for molar acute pulpitis using GuttaFlowR 2，thus to provide a more efficient，comfortable way and lay a basis for simpler treatment. Methods：Totally 90 molar teeth were selected and divid－ed into two groups，45 teeth in A group used GuttaFlowR 2 plus single cone obturation treatment，45 teeth in B group used iRoot SP plus thermoplasticized gutta-percha technique. The treatment time，and the difference of pain index and efficiency between two groups after 24 hours，3 days，7 days，one month and three months were compared. Results：Concerning the treatment operation time，the group A was （63.20±6.54） min，while the group B was （86.12±8.08） min，the group A was significantly better than the group B（P<0.01）. The pain index of group A and group B was （2.40±0.54） and （4.60±1.31） at 24 hours after treatment，and （1.80±0.63） and （3.10±1.23） after 3 days respectively，and the difference was statistically significant（P<0.05）. There was a significant difference between the two groups in pain index after 24 h and 3 days（P<0.05），but no significant difference after 7 days，one month and 3 months（P>0.05）. There was no significant difference in the efficiency at each time point（P>0.05）. Conclusion：GuttaFlowR 2 non-heated flowable gutta-percha has a good therapeutic effect in the treatment of one-visit root canal therapy and has its unique ad－vantage. It can be widely used in one-visit root canal therapy in molars compared with hot gum filling. It also provides a new idea for independent innovation.