Abstract: The reasons were analyzed ,which caused lead and lag errors in vehicle navigation system. A new method was proposed, which using map matching(MM)to correct lead and lag errors in global positioning system/dead deckoning system(GPS/DRS) integrated navigation system. The method made lead and lag errors boil down to GPS errors, which could be emendated by map data on the basis of the observability of GPS errors along the vertical direction . A general Kalman filtering was constructed to process the information of corrected GPS and DRS later, which decreased lead and lag errors in the integrated navigation system. Experimental results show the effectiveness of the proposed method．