Abstract: Objective: To investigate the relationship of the expression of brain-derived neurotrophic factor(BDNF) and tyrosine kinase B(TrkB) to salivary adenoid cystic carcinoma(SACC).Methods: The immunoactivity of BDNF and TrkB in 45 cases of SACC was determined by immunohistochemistry method(streptavidin biotin method).The relationship of the expression of BDNF and TrkB with the histological type,clinical stage,perineural invasion and distant metastasis of the tumor was analyzed.Results: The positive expression rates of BDNF and TrkB were 84.4% and 88.9% in SACC.The statistical analysis showed that the expression level of BDNF and TrkB was positively correlated with the clinical stage and distant metastasis potential(P<0.05-P<0.01),and the expression level of TrkB was positively correlated with perineural invasion(P<0.01).Conclusions: BDNF and TrkB can promote the invasiveness and distant metastasis of SACC,which may act as a predictor of distant metastasis and perineural invasion of SACC.