The invention provides an image fingerprint extracting method, an image fingerprint-based information filtering method and an image fingerprint-based information filtering system. The image fingerprint extracting method comprises the following steps: S1: performing interpolation processing on an original image; S2: blocking the image after the interpolation processing, and performing DCT conversion; S3: performing RGB grey scale processing on converted pictures; S4: quantizing an image result after the grey scale processing; S5, performing lossless compression on the image and outputting a binary sequence; and S6, performing serialized recombination on the binary sequence to obtain the image fingerprint. By using the methods and the system, the speed for identifying and processing data service contents can be greatly improved so that the real-time monitoring of full traffic flow of operator services becomes possible.