The invention discloses a detection device and a detection method for the wear loss of a cutter of a shield machine. A detection probe which is connected with an input end of a detector through a data line is arranged in the peripheral foregoing teeth-cutter of the shield machine, wherein the detector is connected with a programmable logic controller (PLC) control system of the shield machine through a signal output device; and the PLC control system of the shield machine is connected with a touch screen and communicates with the touch screen. The detection device has the advantages that the wear loss of the peripheral teeth-cutter is detected through detecting the height of an alloy strip on the peripheral foregoing teeth-cutter of the shield machine, so the defects in a hydraulic limit type detection manner that an alarm can be given only when the cutter is worn to a certain height is overcome, and thereby the detection device can continuously display measured data in time; through welding the peripheral foregoing teeth-cutter on a cutter holder, the problem that a welded type cutter is difficult to detect is solved; meanwhile, data detected through utilizing a conductive slide wire ring can be displayed and recorded in time in a touched manner in an operating room, so the detection device is more convenient to use; and besides, the detection device has high measurement accuracy, great real time performance and high reliability.