The invention provides an electrothermal film board production method and device. The production method includes the following steps that (1) a substrate to be sprayed is provided; (2) the substrate is sequentially sent to a temperature rising region with the temperature ranging from 0 DEG C to 200 DEG C, a solid temperature region with the temperature ranging from 201 DEG C to 600 DEG C and a stabilizing region with the temperature ranging from 601 DEG C to 620 DEG C to be subjected to temperature adjusting; (3) the substrate is sent to a spraying region with the temperature ranging from 601 DEG C to 620 DEG C to be sprayed by electrothermal film processing liquid, at least one face of the substrate forms an electrothermal film, and a semi-finished product is obtained; (4) the semi-finished product is sent into a curing region to cure the electrothermal film; (5) cooling is conducted, and a finished product is obtained. According to the method, stepwise temperature adjusting is conducted on the substrate before spraying, spraying is conducted after the temperature of the substrate is even, the connection performance of the formed electrothermal film and the substrate is good, the thickness of the film is even, the surface is smooth, and the defects of blistering and irregularity are avoided; one-time spraying is enough, the production efficiency is high, and moving type spraying is adopted, so that spraying is comprehensive, and the film layer is even.