In addition to local recurrence and metastasis, multiple primary tumors are also an important factor defeat the survival of oral cancer.The incidence rate of multiple primary tumors (MPTs) in oral cancer population is 17～30％.The frequency increases in patients with carcinogenic habits.The number, location and attack timing of MPTs are difficult to predict even manipulate.For the dilemma, develop even establish an effective strategy in screening, detecting, diagnosis and management.In south Taiwan, most of oral cancer patients had hazard life habits, such as betel nut chewing.We confront the high MPTs group in oral cancers population, develop some clinical protocol in clinic and laboratory try to detecting the secondary even the tertiary primary as early as possible.The detecting method include the optic way like, autofluorence reflection, chemical stain such as toluidine blue, even the molecular level test.To effective further control after first tumor treatment, modify the subsequently treatment modality to control the secondary tumor, even better to prevent new one arises is one of the major concern in our study.