The invention discloses a flame-retardant processing technology for a flame-retardant plate based on a macromolecular flame retardant, and relates to the technical field of plate processing. The flame-retardant processing technology comprises a high-pressure explosion-proof box, the bottom of the high-pressure explosion-proof box is fixedly connected with a machine box, and the right side of the machine box is fixedly connected with a feeding mechanism. According to the flame-retardant processing technology for the flame-retardant plate based on the macromolecular flame retardant, the pressure pump is arranged to be matched with related pipelines, the high-pressure explosion-proof box can be pressurized, internal air is promoted to circularly flow, heating is conducted in the process, the flame-retardant plate can be uniformly heated and dried, the probability of explosion of the flame-retardant plate can be reduced through pressurization, and the flame-retardant effect of the flame-retardant plate is improved. The flame-retardant plate is fully dried, then the atomized flame retardant is sprayed into the high-pressure explosion-proof box, the fully dried flame-retardant plate can quickly absorb the flame retardant, meanwhile, part of steam is mixed in the atomized flame retardant, the fumigation effect can be achieved, the flame retardant can penetrate into the flame-retardant plate more deeply in cooperation with the pressurization effect, and compared with simple soaking, the flame-retardant effect is better, and the service life of the flame-retardant plate is prolonged. And more flame retardants can be absorbed, and the efficiency is higher.