Slope Detection with road lane detection using Image Processing is one of the methods used to detect boundaries of the road using a different range of color from the road environment to distinguish road lane and non-road lane. This research using the road lane detection method that is inspired and based on previous research that we modified and develop to detect the slope of the road using OpenCV libraries and Linear Regression Method. Detection is done by making an intersection line from upper and down line that detected from Image Processing. This Research using a truck prototype with a 1:11 dimension to simulate the system and using prototype road to with the same dimension of the truck. The result shows that system can detect the slope of the road with accuracy reaching 90%