The present invention provides parking guidance methods for a vehicle, which comprises: calculating an estimated backward track of the vehicle from a current steering angle detected by a steering angle sensor; calculating an estimated parking space from the estimated backward track and a relative angle inputted by a driver through an input means; converting coordinates of the calculated estimated backward track and estimated parking space into image coordinates; synthesizing the converted image coordinates with an image acquired by a camera provided at the rear of the vehicle; and displaying the synthesized image on a monitor of the vehicle. The methods enhances driver's convenience and safety in the event of back-in perpendicular parking.