The invention relates to a folded bill identification method and device. The device comprises a bill input port, a signal collection module, a signal identification module and a receiving / rejecting module, wherein the signal identification module further comprises a first high-pass filtering unit, a first low-pass filtering unit, a second high-pass filtering unit, a second low-pass filtering unit, a difference filtering picture unit, a first feature extraction unit, a second feature extraction unit, a third feature extraction unit and an identification decision unit. According to the folded bill identification method and device, features are classified effectively in a high / low pass filtering manner, so that the distinguishability of the features are improved; especially, different types of features correspond to different classifiers; furthermore, the classifiers have similar functions with an Adaboost classifier and can ensure the identification confidence level, so that an identification system is relatively robustly compatible with complex situations, such as external environment interference and bill body pollution; the whole folded bill solving method and device can effectively identify folded bills.