Abstract: With progress of multi-GNSS (GPS/GLONASS/Galileo/Compass) and multi-mode receiver chip development, precise orbit and clock offset determination of navigation satellite as well as multi-GNSS data fusion under unified space-temporal reference frame have become key problems in the multi-GNSS integrated application. Based on the self-developed software PANDA, this paper carries out investigations on integrated precise orbit and clock offset determination of multi-GNSS (GPS/GLONASS/Galileo/Compass). Then precise orbit and clock offset determination of GPS, GLONASS and GIOVE have been implemented through actual global multi-mode receiver data, including GPS/GLONASS, GPS/Galileo experimental satellites (GIOVE). By comparison with IGS provided precise orbits for GPS and GLONASS, together with differences of orbit overlap arc, and SLR observable validation, accuracy of the integrated precise orbit have been evaluated. Results show that the 3-D orbit precision of GPS and GLONASS obtained from PANDA and the data fusion method introduced in this paper reach 2.5cm and 6.0cm respectively, while the 3-D orbit precision of GIOVE satellite is superior to 30cm, and the radial precision reaches 10 cm.