Objective To investigate the clinical effect of periodontal combined pulp therapy and periodontal therapy alone in severe periodontitis. Methods A total of 62 patients with severe periodontitis admitted to our hospital from January 2017 to January 2019 were selected as the research subjects and divided into the observation group and the control group according to the random number table method, with 31 cases in each group. The observation group was treated with periodontal combined pulp, while the control group was treated with periodontal alone. The periodontal bag probing depth (PPD), gum crevicular bleeding index (SBI), mobility (MD), plaque index (PLI) before and after treatment and therapeutic effect were compared between the two groups. Results There were no significant differences in PPD,SBI, MD and PLI between the two groups before treatment (P＞0.05). The PPD, SBI, MD and PLI of the two groups after treatment were lower than those before treatment, and the differences were statistically significant (P＜0.05). The PPD,SBI, MD and PLI of the observation group after treatment were lower than those of the control group, and the differences were statistically significant (P＜0.05). The total effective rate of the observation group was higher than that of the control group, and the difference was statistically significant (P ＜0.05). Conclusion The clinical effect of periodontal combined pulp therapy in patients with severe periodontitis is superior to that of periodontal therapy alone,and it is worthy of promotion and application.