Abstract: In order to achieve the ability of rapidly detecting and accurately locating X corners,a real-time method to locate X corner is proposed.Firstly,the image is filtered to find X corner candidates according to symmetry and intensity distribution characteristics of X corner image,and then the segment test is performed for each X corner candidate to confirm it's a X corner,find edges and localize corner in sub-pixel.Experiments show that compared with Harris algorithm,the method can detect X corners and eliminate other corners,provides better positioning accuracy and higher detection speed, and has the capability to process PAL images online and in real time.