The present invention provides a method for updating GPS ephemeris data, which is applicable to a navigation device containing a GPS ephemeris data. The method for updating GPS ephemeris data includes the following steps: first, the navigation device counting down a predetermined time; next, searching a GPS ephemeris data server through a network interface; then performing a download from the GPS ephemeris data server so as to update the GPS ephemeris data in the navigation device. Accordingly, the time required for updating ephemeris data is shortened.