Abstract: Global Positioning System signal is easily interfered by the complex city environment and sometimes is not reliable. There are some "blind spots" of dead reckoning for vehicle navigation in city.Aiming to solve these problems, this paper integrates Dead Reckoning (DR) with the GPS system and establishes integrated positioning system. This paper also designs the filter model of the GPS/DR integrated positioning system, analyzes the information sharing principle and calculation of information distribution coefficient.