Circuit board of LED display device, preparation method of circuit board and LED display device

The invention relates to a circuit board of an LED display device, a preparation method of the circuit board and the LED display device, and the circuit board of the LED display device comprises a first circuit layer and a second circuit layer arranged on the bottom surface of the first circuit layer. The first circuit layer comprises an A-pole bonding pad and a B-pole bonding pad which are not in contact with each other, and an insulating material filled between the A-pole bonding pad and the B-pole bonding pad; the second circuit layer comprises an A-pole pin and a B-pole pin which are not in contact with each other, and an insulating material filled between the A-pole pin and the B-pole pin; wherein the A-pole pin is in contact with at least one A-pole bonding pad, and the B-pole pin is in contact with at least one B-pole bonding pad. The circuit board of the LED display device is composed of the two circuit layers, no supported insulating substrate is arranged between the two circuit layers, and the thick