Intelligent systems capable of automatic localization and methods using the same are disclosed. An intelligent system includes an intelligent robot and a plurality of face recognition devices each in a wireless connection with the intelligent robot. Each face recognition device is disposed at the entrance of a room, and is configured to identify face information of people in the room and transmit the face information to the intelligent robot. The intelligent robot thus updates a database according to the face information and automatically identifies a location of a subject to be served based on the database. Thus, the present disclosure can automatically identify the location of the subject to be served.