The invention discloses a multi-path depth encoded information fingerprint extraction method based on the bit space. The method comprises a first step of constructing a bit window; a second step of constructing a bit plane; a third step of reducing dimensions and constructing a bit chain; a fourth step of encoding the bit chain; and a fifth step of comparing fingerprints. The fourth step includes conducting transversal and statistics for the constructed bit chain with reduced dimensions, acquiring the number of continuous 0 and the number of continuous 1 in sequence, and constructing a new decimal sequence of number; and binarizing the obtained decimal sequence of number to obtain a new binary bit chain with the first bit not being 0, repeating the transversal and statistics operation for the obtained bit chain, carrying out loop iteration in sequence until the newly obtained decimal sequence of number has only one element, and recording the value of the element obtained at last and the number of times of loop iteration as a feature value of an information fingerprint feature space The invention has the advantages of improving the efficiency in the same information detection and the like.