Abstract: Objective：To explore the effect of vitamin C on the development of the induced rat periapical periodontitis. Methods：Periapical disease was induced by pulp exposure of the mandibular first molar on 100 male Wistar rats (8-week-old). Rats were divided into vitamin C groups (0，0.1, 0.5 and 1 mg/mL, respectively) and a normal group, then were sacrificed on day1, 3, 7, 14 and 21. We measured the area of the periapical lesions by radiographs and obtain histological results by HE staining. Results：Periapical lesions were significantly expanded from day 3 onwards, in a time-dependent manner, and peaked on day 21. There was no difference between day 1 and 3. On day 7,14 and 21，the periapical lesion areas of practiced groups were remarkably lower than that of the control group. The periapical lesions of the 0.1 mg/mL group was the lowest among all practiced groups. Vitamin C groups also had less bone resorption lacunae and smaller alveolar bone destruction. Conclusions：To some extent，vitamin C effectively inhibited the progress of the rat periapical periodontitis.