The invention discloses a press on-line damage detection device for a filter board of a filter press and an enforcement method. The filter press on-line damage detection device comprises a plurality of fiber grating sensor inserts which are embedded in the filter board of the filter press; the fiber grating sensor insert is connected to a filter board fiber coupler; the filter board fiber coupler is connected to a fiber grating demodulation instrument through the filter press fiber coupler and a fiber concentrator; a detection light signal generated by the light source enters the fiber grating sensor insert in the filter board and is returned to the fiber grating demodulation instrument after the interference and reflection by a raster zone; the fiber grating demodulation instrument analyzes the center wave length change of the optical signal and transmits the demodulated signal to the processor; the processor establishes a three-dimension geometric model of the filter board according to the temperature and strain which are collected by the fiber grating sensor inserts, and performs calculation on the damage degree of the filter board and the residual strength. The invention can realize the on-line damage detection of the filter board of the press filter. The filter board of the filter press on-line damage detection device can realize the on-line damage detection on the filter board of the press filter and has advantages of easy operation, one-time installation and long time use.