This paper studies the coordinate systems and the time conversion relationship between GPS and GLONASS, combined with the observation equation of a single Pseudo-range positioning system. It deduces Pseudo-range observation equation under integrated positioning and its solution, then programming it. Experimental analysis shows that positioning accuracy of GPS / GLONASS integrated system is much better than a single positioning system in the case of poor observing conditions. Applied to LBS System, this system will improve the quality of LBS and promote the development of LBS.