〔Abstract〕 Objective To evaluate the effect of 2.5%NaClO solution as irrigating agent on the healing of dental pulp after preservation treatment in rats with inflammatory pulp. Methods 48 maxillary molars of 24 8-week-old male SD rats were selected and pulpitis models were established by pulp cavity exposure for 24 hours. Then part of the crown pulp was removed and divided into two groups according to different irrigation methods: 2.5%NaClO flushing group(NaClO) and saline flushing group(NS). The pulp was covered with iRoot BP Plus and the cavity was sealed with glass ionomer. Four animals in the two groups were killed on the 1st, 7th and 28th day after operation, respectively. And the inflammatory reaction, tissue destruction and hard tissue formation of residual dental pulp tissue were observed and evaluated by histopathology. Results The pulp inflammatory reaction, tissue destruction and restorative dentin formation in 2.5%NaClO irrigation group and saline irrigation group were similar on the 1st, 7th and 28th day after operation, there was no significant difference between the two groups. Conclusion 2.5%NaClO used as a hemostatic before iRoot BP Plus pulp capping after partial pulpotomy has similar effect with normal saline on the inflammatory pulp model of rats, and does not affect the healing of pulp inflammation.