Objective: To study the clinical efficacy of biological ceramics (iRoot BP Plus ) and mineral trioxide aggregate (MTA) in direct pulp capping of mature permanent teeth, to provide referrence for clinical application. Methods : Seventy-four patients with pulp exposure due to deep caries or reversible pulpitis in 75 mature permanent teeth were selected and were randomly divided into two groups. iRoot BP Plus were used as pulp capping agents in the treatment group and MTA were used as pulp capping agents in the control group respectively. The clinical efficacy and imaging analysis were performed at 1, 3, 6 and 12 months after operation. Treatment success rate of the two groups were calculated, and the influence of various factors including gender, age, tooth position, cavity, number and size of pulp exposure on the efficacy of direct pulp capping were analyzed. Results : Sixty patients with 61 mature permanent teeth were selected. Twelve mouths after treatment, 61 teeth of 60 patents were completely investigated (iRoot group: 31 teeth 30 patients; MTA group: 30 teeth 30 patients). The success rates of the 2 groups were 90.3% (iRoot BP Plus) and 90.0% (MTA), respectively. There was no statistical difference between 2 groups (P>0.05). Statistical analysis also showed that gender, age, tooth position, cavity, number and size of pulp exposure had no significant difference between the two groups (P>0.05). Conclusion Both iRoot BP Plus and MTA are effective in direct pulp capping of mature permanent teeth with carious pulp exposure, while the operation of iRoot is simple and convenient.