A method for processing marine products includes a plurality of steps. First put natural charcoal in a vacuum oven and draw air out of the vacuum oven. Second, heat up the interior of the vacuum oven to let charcoal produce carbon monoxide and water vapor, and third, cool carbon monoxide in a cooling tank to room temperature. Fourth. separate carbon monoxide from water vapor and draw carbon monoxide into an air bag. Fifth, draw the carbon monoxide in a marine food processing device to let carbon monoxide function to settle iron contained in marine food to remain in the meat of marine food to keep fresh red color and freshness of marine food.