1. A method of extracting and reconstructing court lines, comprising the steps of: binarizing a court image of a court including a court line to form a binary image; searching for a plurality of corners in the binary image and defining a court line range by the corners; forming a plurality of linear segments from an image within the court line range by linear transformation; defining at least one first cluster and at least one second cluster according to the characteristics of the linear segments, and categorizing the linear segments into a plurality of groups according to the first cluster and the second cluster; taking an average of each group as a standard court line, and creating a linear equation of the standard court line to locate the position of a point of intersection of the standard court lines; and reconstructing the court line according to the point of intersection.