An apparatus and a method for detecting a vehicle location in a navigation system are provided. A travel angle difference and lateral and longitudinal inclinations of the vehicle are used to accurately detect the vehicle location if a vehicle location is estimated using detection signals from a sensor unit installed on a vehicle. If a value of DOP (Dilution of Positioning) of a navigation message received by a GPS (Global Positioning System) receiver is equal to or greater than a predetermined threshold, reference vehicle location information is set using vehicle location information just previously map-matched and the detection signals from the sensor unit. The vehicle location is detected using the set reference vehicle location information and the detection signals from the sensor unit.