Plane detection method and device

The invention provides a plane detection method and device. The method is characterized by, in the process where a transmitting mechanism transmits objects to be detected, detecting distance between the objects to be detected and a plurality of sensors through the plurality of sensors uniformly distributed in a detection device; then, carrying out calculation on the obtained multiple distance data by utilizing a median line theorem; and determining the objects to be detected, the plane bending degree of which does not meet standard and rejecting the unqualified objects based on the calculation result and a preset error range. Therefore, through the provided plane detection method, cathode plates can be detected automatically without stopping; the unqualified cathode plates are rejected automatically, thereby improving work efficiency, saving labor and preventing false detection and missed detection due to manual detection; and the plane detection device is small in size and convenient for work personnel to ca