Provided are a disconnection method and a disconnection device for a patterning substrate, and the method and the device do not cause non-separation and substrate damages. The invention provides the disconnection method and the device for a patterning substrate whose surface of a fragile material substrate is provided with an electronic circuit pattern. The method comprises a laser processing process (a laser processing device (A)), sticking the patterning substrate (W) on an extending adhesive tape (2), illuminating laser on the surface of the patterning substrate (W), to form a plurality of disconnection starting points (5) along a preset disconnection line (L); a specified position disconnection process (a specified position disconnection device (B)), using incomplete parts of the disconnection starting points (5) formed in the laser processing process as specified positions, applying external pressure on the specified positions to make the patterning substrate (W) flexible, to make the patterning substrate (W) disconnected; and an extending disconnection process (an extending disconnection device (C)), extending the extending adhesive tapes (2) to apply tensile stress on the patterning substrate (W), to disconnect all preset disconnection lines (L).