A system for providing position information by using a wireless personal area network (WPAN), and a method of acquiring the position information of a mobile device thereof where the system includes: a first node including referenced position information; and a plurality of second nodes calculating their respective position information based on the reference position information of the first node, wherein the mobile device calculates its position information by using the reference position information received from the first node and/or one or more of the respective position information of the second nodes. According to the system and method, at an indoor place where a global positioning system (GPS) signal is weak or absent, the GPS position information can be acquired through the position information providing system using a low-price wireless LAN communication network.