A speed dialing method for displaying contact information for use in a mobile communication device is disclosed. Plural time threshold values and information display transparencies corresponding to the time threshold values, respectively, are defined. When the mobile communication device receives a trigger signal generated by pressing a button and a time for continuously receiving the trigger signal respectively reaches the time threshold values, contact information corresponding to the pressed button is displayed with information display transparencies corresponding to the time threshold values on a screen of the mobile communication device. When the time for continuously receiving the trigger signal reaches a dial threshold value, a contact phone number assigned to the pressed button is dialed by the mobile communication device.