At present,the purpose of anti-stealth has been achieved by improving diffuse reflectance signal strength for the most advanced anti-stealth radar,while it is impossible to achieve the fundamental anti-stealth by this method. So,a new radar anti-stealth technology is proposed and by means of straight edge diffraction it can be realized in measuring and tracking stealth flying objects. When scanning the stealth flying object with laser,not only the position and the flying speed of the stealth flying object can be simulated,but also the shape and size can be obtained. Thus,it can be realized in full tracking the stealth flying objects. In addition,the radar of using the principle of straight-edge diffraction has the functions of data encryption.