The invention discloses an externally spiral PDC drill bit (see the corresponding figure) with replaceable cutting teeth and provides a spiral PDC drill bit with detachable cutting teeth. The spiral PDC drill bit mainly comprises the integrated cutting teeth (see the corresponding figure) and taper cutters, and is characterized in that the cutting teeth of the drill bit can be in threaded connection with threaded holes in cutter blades so that the abraded cutting teeth can be replaced; the outline of each cutter blade is in a spiral shape, and by means of the structure, drilling is easy to implement in the drilling process; and the three taper cutters (being zero degree in the figure) are welded to the center portion of the drill bit, and the structure of the taper cutters is beneficial to reducing drilling resistance in the drilling process. According to the drill bit, the drilling resistance is reduced, so that the drilling process is easier to implement, the problem that a whole drill bit has to be abandoned no matter which cutting tooth is broken down is solved fundamentally, cost is reduced, and the work efficiency is further improved.