In order to solve the problem that sunlight flashing can generate false signals in omni-directional laser detection easily, on the basis of adjacent frames subtracting, a method distinguishing false signals according to the image characteristics is presented. The effect of the false signal suppressing is verified in natural environ?ment with blazing sunshine, and the results indicate that relative to the method of filtering technology and improv?ing frame frequency, this method can solve the problem of suppressing false signals generated by sunlight flash?ing. For the imaging detector and the image acquisition card with low requirements, it has good application value.