The invention discloses a backing plate for drilling of a PCB (printed circuit board) and a preparation method of the backing plate. The backing plate comprises a wood fiber plate as well as ultraviolet radiation cured resin layers applied to the upper surface and the lower surface of the wood fiber plate, wherein the ultraviolet radiation cured resin layers have the performance of radiation curing through ultraviolet radiation curing LED lamps. The backing plate obtained after ultraviolet radiation curing by the ultraviolet radiation curing LED lamps has the advantages of smaller warp deformation, higher smoothness, more easily acceptable appearance, extremely light odor, higher hardness, long service life and environmental protection. Besides, a heat dissipation device is arranged on a conveying device, so that the heat influence on the backing plate in a preparation process can be reduced effectively, the warp degree of the backing plate is further reduced, and the smoothness of the backing plate is further improved.