A membrane circuit board includes a first film substrate, a second film substrate, an insulating spacer substrate and a waterproof structure. The first circuit layer is installed on the first film substrate. A second circuit layer is installed on the second film substrate. The insulating spacer substrate arranged between the first film substrate and the second film substrate. The first circuit layer is arranged between the first film substrate and the insulating spacer substrate. The second circuit layer is arranged between the second film substrate and the insulating spacer substrate. The waterproof structure includes a first welding layer and a second welding layer. The first welding layer is arranged between the first film substrate and the insulating spacer substrate. The second welding layer is arranged between the second film substrate and the insulating spacer substrate.