This paper proposes an algorithm for parking assist system. It detects a parking slot and estimates the pose of the parking slot. User touches the parking slot that wants to park at the display showing rear view. Then, an ROI is set based on the touch point. Parking slot is detected in the ROI using Hough transform. NCC (Normalized Cross Correlation) is used to get the pose of parking slot. It successfully detects parking slot and estimates the pose. But, there is a problem due to the scene change causing variation of parking slot at rear view when vehicle enters the parking slot. To solve this problem, the process of pose estimation is separated into phase 1 and phase 2 according to applied template shape.