Abstract: In order to remedy the main shortcomings of current map matching algorithms, that the effects of position correction along road for GPS positioning are poor, especially to the case of independent GPS positioning, a map matching algorithm was designed based on the characters and distribution rules of GPS positioning errors. The focus lied in improving position precision along road for GPS positioning. The algorithm was verified with measured GPS data based on part road network in Changchun, China. The results show that the effects of map matching algorithm are better than conventional algorithms, especially that the position correction precision along road for GPS positioning is improved by 2.5 m, which can meet the higher demand for GPS data users well.