The invention provides a dual-component high-pressure proportion-adjustable fire retardant coating spraying device and method. The dual-component high-pressure proportion-adjustable fire retardant coating spraying device comprises a control mechanism, a main air feed pump, a feeding mechanism, a heating mechanism, a proportioning mechanism, a spraying mechanism and a cleaning mechanism. The control mechanism is a digital electronic controller, the input end of the main air feed pump is connected with an external air source, the output end of the main air feed pump is connected with the feeding mechanism, the heating mechanism, the proportioning mechanism, the spraying mechanism and the cleaning mechanism through an air pressure adjusting device, and a switch of the main air feed pump is connected with a main air switch of the digital electronic controller. The dual-component high-pressure proportion-adjustable fire retardant coating spraying method includes the steps of adding A-component coatings and B-component coatings into an A-component coating bucket and a B-component coating bucket; heating the A-component coatings, the B-component coatings and coating pipes; when the temperature of the A-component coatings and the temperature of the B-component coatings reach the set temperature, adjusting the proportion of the A-component coatings to the B-component coatings, and carrying out proportion testing; mixing the A-component coatings and the B-component coatings through a far end mixer; adding the A-component coatings and the B-component coatings which are completely mixed into a mixed coating pipe; carrying out spraying; cleaning the device after spraying is completed; stopping the device. The spraying efficiency is high, and the coating quality is good.