Abstract: Objective：Simvastatin chitosan-glycerophosphae gel, was used for sustained release of simvastatin, and an experimental model of pulpotomy in rats was established, so as to explore the role of simvastatin after dental pulp injure. Methods：Chitosan-glycerophosphae gel and chitosan thermosensitive hydrogel loaded with simvastatin into the gel was prepared. The controlled release of simvastatin, as measured by UV spectrophotometry , was monitored for 60 days. Pulpotomy in rat maxillary first molars, using simvastatin chitosan gel(S-C-GP), chitosan gel(C-GP), and calcium hydroxide as direct pulp capping materials，and the contralateral teeth were used as controls. 1, 3, 7, 14 and 28 days after the operation, animals were sacrificed. X-ray observation was carried out in 30 minutes, then slicements were HE stained after EDTA decalcified. Results： Chitosan thermosensitive hydrogel solidified within 15 minutes at 37 ℃, and simvastatin chitosan thermosensitive hydrogel solidified within 8 minutes at 37 ℃. During monitoring of the controlled release, after a short and fast 48 h release, a stable release process could be observed no less than 60 days. The percentage of cumulative release was about 61.5% within 60 days. High density image in the root canal orifice could be seen in Ca(OH)2 28 d group, while in S-G-CP group, it could be seen earlier in 7 d,14 d, and 28 d group. The HE stain of S-G-CP 7d and 28d group shows difference with Ca(OH)2 group in the progress of repairtive dentinogenesis, and the S-G-CP group shows better histocompatibility and earilier repairtive dentinogenesis. Conclusions：The chitosan thermosensitive hydrogel as a carrier, loaded simvastatin, has a sustainable release of the active simvastatin. Animal experiments, simvastatin chitosan gel for vital pulp after direct pulp capping, show its potency in promoting the tertiary dentinogenesis. It is an experimental evidence for simvastatin as a direct pulp capping material in vivo.