The invention provides a delayed coking blowdown system and method for preventing the flameout of a refinery torch. The method for preventing the flameout of a refinery torch comprises the following steps: introducing a medium from an air cooler of the delayed coking blowdown system into a liquid separation tank to perform a gas-liquid separation procedure after the medium goes out of the air cooler of the delayed coking blowdown system and before the medium goes into an aftercooler; and then introducing a gas phase obtained through the gas-liquid separation procedure into the aftercooler for cooling. The delayed coking blowdown system comprises the air cooler and the aftercooler arranged at the downstream of the air cooler. The delayed coking blowdown system also comprises the liquid separation tank connected between the air cooler and the aftercooler; and a medium from the air cooler is introduced into the liquid separation tank, and a gas phase obtained through gas-liquid separation is introduced into the aftercooler for cooling. The invention can prevent wax hanging of the aftercooler, ensure the heat exchange effect, and avoid production-suspended overhaul, torch flameout and other accidents.