Abstract: Adenoid cystic carcinoma(ACC)often occurs in head and neck, many patients are treated with surgical operation combined radiation treatment method in clinic.Surgery combined radiation therapy can achieve good local control, especially for those late-stage cancer undlgo patients who cannot undergo surgical resection.Radiation therapy can alleviate local symptoms, retards the growth of tumor. ¹²⁵I seed interstitial brachytheraphy is an effective treatment method which has the characteristics of minimal damage in normal tissue, accurate positioning in target area and simple operation, and it can be one-time completed.¹²⁵I seed can be implanted in tumors through the CT, B ultrasonic and image navigation equipment.Application of ¹²⁵I seed interstitial brachytheraphy treatment in head and neck ACC has achieved good short-term curative effect. Preoperative establishing treatment plan and intraoperative or postoperative quality verification can guarantee the qualityoftreatment and make ¹²⁵I seed interstitial brachytheraphywork better.