The utility model relates to an air cooling island freezing proof technique field, in particular to flow control system prevents frostbite on air cooling island. This flow control system prevents frostbite on air cooling island including six parallelly connected air cooling islands connecting the steam device, wherein two is listed as the air cooling island and reserves the steam extraction, and all the other four are listed as that the air cooling island is whole seals its characterized in that: be provided with the big butterfly valve of admission on the air cooling island, all be provided with the bypass of three kinds of different pipe diameters on the air cooling island of two reservations, be bypass A, bypass B and bypass C respectively, all be provided with the valve in the above -mentioned bypass. The utility model discloses simple structure can guarantee to reserve the frostproofing requirement of - 30 DEG C air cooling island adaptations to as much as possible utilizes unit steam extraction waste heat, retrieves the cold source loss, reaches the purpose that reduces unit power generating coal consumption and increase heating capacity, has very superior economic benefits.