The invention relates to the related technical fields of set-top boxes, in particular to a set-top box used by a plurality of users and a starting method thereof. The set-top box comprises a FLASH module capable of storing programs and configuration data, a display interface module, a remote controller interface module, other input and output equipment interface modules and a master control module connected with and controlling all the modules, wherein the master control module further comprises a login module, a user information loading module and a user information storage module. By the set-top box and the starting method thereof, only functions corresponding to a user are loaded after the selection of the user in the starting of each time, so starting time can be shortened, the user can use each function in a selected system, the functions can be switched conveniently, and operating complexity is further decreased.