The invention provides a long-time iodine flow supply device, and relates to the technology of gas supply of a continuous wave oxygen-iodine chemical laser. The main body of the device has two parts: an electric heating iodine vapor storage tank and a combustion chamber for the combustion of two types of gas. The electric heating iodine vapor storage tank enables solid iodine to be heated to a certain temperature and enables the solid iodine to be changed into liquid iodine. Moreover, there is iodine vapor with a certain saturated vapor pressure on the liquid level. The combustion chamber is a closed space which is used for the combustion of carbon monoxide and oxygen, and the generated high-temperature and high-pressure gas enters the iodine vapor storage tank after the temperature adjustment through diluent gas. High-temperature carbon dioxide gas enters the liquid phase of the iodine vapor storage tank and then forms bubbles, thereby enabling heat energy to be transferred to the liquid iodine and enabling the iodine to be vapored into iodine vapor, wherein the bubbles comprise iodine vapor with a certain density. When the bubbles continue to rise in the liquid phase, the phenomenon of mass and heat transfer continues to happen till the balance is reached. The bubbles flow out from the liquid phase, enter a gas phase, pass through a gas supply pipe and then enter a laser main body.