A COF circuit board, a display device, a signal processing method and a bridging chip are provided. The COF circuit board includes: a flexible circuit board, a driver integrated circuit and a bridging chip disposed on the flexible circuit board, wherein the flexible circuit board is further provided with a first connecting terminal and a second connecting terminal. An output end of the driver integrated circuit is electrically connected to the first connecting terminal. The bridging chip includes N first registers, M second registers and a controller, wherein the N first registers are electrically connected to an input end of the driver integrated circuit, the M second registers are electrically connected to the second connecting terminal, the controller is configured to write values in the M second registers into the corresponding N first registers according to a register corresponding relationship.