In order to resolve the problem that scattering laser warning can only localize the scattering laser spot, but cannot trace back to the enemy laser source at the present time, A three-dimensional (3D) model in war field circumstances including the enemy laser source, the scattering laser spot on some flat and omni-directional laser warning systems is established. The analytic expressions of the scattering laser spot contour on flat and the object space half-field angle of any point on the contour relative to fish eye lens were obtained. Then the spot imaged on sensor was fish eye distortion corrected. And the points on spot edge were selected, accordingly the parameters of 3D model were acquired. Whereafter the parameters were combined with information of sensor array, thus azimuth and distance of the enemy laser source relative to the system could be attained finally. In the end the experimental results validated the method, the cause of errors was analyzed.