Abstract: The laser eavesdropping technology does not directly irradiate the eavesdropping target and due to the scattering of the glass, the existing intercepted laser warning technology has no ability to obtain any information of the eavesdropping source. Aiming at this problem, an anti-laser eavesdropping warning system by staring at the windows using a charged coupled-device(CCD) camera and optical filter was proposed. At the same time, the space geometric model for the eavesdropping laser source, the scattered spot on glass and the anti-laser eavesdropping system was built, the image feature extraction algorithm such as the edge extraction and the least squares image fitting algorithm were used to fit the scattered laser spot contours, and finally, the mathematical model of eavesdropping laser light source was deduced. The experimental results show that, the laser eavesdropping warning system not only can detect the eavesdropping spot which is irradiated on the glass, but also can be traced back to the azimuth angle and pitch angle information of the laser beam, with positioning accuracy ≤ 4°, thus the purpose for locating the eavesdropping source position is achieved. The anti-laser eavesdropping early warning system and eavesdropping source localization technology mentioned can help to promote the further development of the existing laser warning technology, and play an active role in national defense security and other fields.