Most scholars regard Buddhism in SUI-TANG- Dynasty as sect period recently ,although never was the concept about the definitions and numbers of sect certain. There are some scholars who have been pointing that sects fibbing by ancient monks. When did the theory of Sect-Buddhism start? Did Tan-Dynasty or others obtrude to Tan-Dynasty’s monks?Have found that the biography of Tan-Dynasty’s monks never alluded a word of sect。Tan-Dynasty’s monks emphasized the succession of teachings from master to disciples , and they didn’t have the notion of religious sects. That the concept of religious sects relate to dauntuung(道統) of Suhng-Dynasty is believed. Religious sects began from Five-Dynasty(五代) and formed at South-Suhng-Dynasty. Arguement about sect numbers and definitions began at early of R.O.C..In that time ,whether the numbers of sect were 9,13 or 15 was mainly argued. However ,those disputations started because of the confusion of dautung and schools but not truly descriptions based on historical evidence. Therefore ,this essay is aimed at corroborating the concept of sect-Buddhism.