Radiation-induced mucositis (RIM) is a common side effect of radiation therapy in head and neck cancer patients. So far, management has been directed to to supportive cares such as mouth rinse with anesthetics, nutritional support, infection treatment, or systemic administration of keratinocyte growth factor or radioprotectors. Whereas these interventions have been valuable for clinical management, they have not been efficiently or collectively directed to molecularly targeted prevention and treatment. RIM is an inflammation-associated disease, because reactive oxygen species and proinflammatory cytokine such as IL-1β and TNF-α were detected in mucositis tissue. Antrodia camphorata (AC) is a typical Chinese herb found only in Taiwan, and it has anti-inflammation, antioxidant and immunomodulatory properties. This study established a RIM mice model via local irradiation of single dose—37.5 Gy toward snout and observes the dorsal surface mucosa of tongue for evaluating the clinical and histopathological changes. Water or AC was feed from day 5 before iiradiation. After irradiated on day 0, each group of mice were sacrificed on day 0, 3, 6, 9, 12, and the tongue were incised for histopathological analysis of epithelial thickness, mast cells counts and pro-inflammatory cytokine gene expression. The body weight began to decline after radiation exposure, but there were no significant differences; epithelial thickness of dorsal surface mucosa revealed gradually descending amount of thickness from tongue posterior toward tip in both groups; AC group showed generalized thicker than the water group. In addition, AC group seemed to have the effect that inhibits mast cell hyperplasia or recruitment. Gene expression profiles of pro-inflammation cytokine showed no significant difference. We also established the grading system of dorsal surface mucosa in RIM mice model. In conclusion, the radiation induced mucositis mouse model was established and we founded that AC would ameliorate RIM in mice.