Abstract: An algorithm for extracting minutiae based on differential code is proposed to overcome the defects of time-consuming and getting many spurious minutiae of traditional ways based on ridge thinning.At the beginning,differential code is got by tracing ridge boundary;subsequently,the turning points are detected,as the differential code is of special characteristic for different boundary features,and the detected points are the locations of the fingerprint minutiae.Three different methods are compared with the proposed approach.The results show a global improvement in detection efficiency and accuracy.