An illumination device and a vehicle lamp illumination system. The illumination device comprises a heat sink (1), a substrate (2), at least one first illuminant (3), a reflective cup (4) and a central light supplementing module; the substrate (2) is arranged in the central area of the reflective cup (4); the heat sink (1) is arranged on one end of the substrate (2); the first illuminant (3) is arranged on at least one side of the substrate (2); the reflective cup (4) is arranged behind the first illuminant (3), and is used to collect a first light ray emitted by the first illuminant (3) and reflect the first light ray to the opening direction of the reflective cup (4) to form a first illumination (20); and the central light supplementing module is arranged in the central area of the reflective cup (4) to emit a central illumination (10). The superposition of the central illumination (10) and the first illumination (20) can improve the illuminance of the central area of the illumination device.