The core of single-position 12-port selector valve head is made of special materials. The central hole of the valve serves as the public channel and can be switched to other channels through the rotor, and the upper lid that touches liquid can be made of different materials suitable for diverse work scenarios. The key raw materials are all imported from overseas, and therefore the valve is suitable for all corrosive liquids like strong acid and alkali. It is extensively applied to the collection and distribution of liquid samples, environment-monitoring instruments, experimental analysis instruments, medical analysis instruments, chromatographic instruments etc.