The invention discloses a camera lens occlusion detecting system and method. The system comprises an image collection module, an image pre-processing module, a background establish module, a high-frequency component extraction module, a generalized image establish module, a suspected occlusion area detection module and an occlusion area determining module, wherein the background establish module is used for acquiring a smooth background image; the high-frequency component extraction module differentiates an initial image and the background image to acquire a high-frequency component distribution graph; the generalized image establish module combines an enhanced image and a pre-processed initial image to establish a generalized image, and performs edge extraction on the generalized image and the generalized image is convolved; the suspected occlusion area detection module compares a convolution result with a preset threshold, and determines that the suspected occlusion area is a candidate occlusion area if the convolution result is less than the preset threshold; and the occlusion area determining module traces the subsequent image pixel value of the suspected occlusion area, and determines that the suspected occlusion area is an occlusion area finally if brightness variations of all the pixels in the area are less than the preset threshold. By using the system and the method, whether the lens is occluded or not can be effectively judged.