Runway is the most significant sign of airport because of its obvious line and edge features, so traditional methods always use the Hough transform to accomplish the detection. Given the problems that Hough transform needs to consider a lot of factors which spends a lot of time, and there are any breakpoints in results, an improved algorithm based on Hough transform is proposed. First, using the idea of straight-line support range, the range of the phase angle is reduced to a small area to detect, which greatly reducing the amount of computation. Then, the line segments which satisfy certain conditions and have the breakpoints are connected based on the method of line connection. Finally, according to the characteristics of the runway, the unrelated parallel lines are removed, the airport runway is figured out quickly and accurately.