An inkjet print cartridge and a method of identifying the colors of ink contained therein by a color flexible PCB are disclosed. The inkjet cartridge includes a casing and a flexible printed circuit board (PCB). The casing has an ink reservoir for containing ink. The flexible PCB, disposed to the casing, includes a flexible substrate, a conductive trace, and a printing ink layer, wherein the flexible substrate has a first surface, and the conductive trace is formed thereon. The printing ink layer is formed on the first surface of the flexible substrate, and the first surface is partially covered by the printing ink layer to bare parts of the conductive trace. Also, at least one identifiable area is formed at the printing ink layer for identification, wherein the color of the identifiable area is associated with the color of ink in the ink reservoir.