The utility model relates to a float formula device of feeding in box with a net under water belongs to the device field of feeding, include and add the feed bin, it is connected to the pipeline of feeding through the trunk line to add the feed bin, it is equipped with the discharge opening of discharge bait on the pipeline to feed, the pipeline of feeding appears for the ring, trunk line and feed and be equipped with the blending bunker between the pipeline, the blending bunker passes through the lateral conduit with the pipeline of feeding and is connected, there is immersible pump A through the pipe connection on the trunk line, the blending bunker has immersible pump B through the pipe connection, be fixed with the floater on the trunk line, the bait scope is big and even, extrusion friction and fight when avoiding the fish forage show, feed under water and to avoid the seabird to rob edible fodder.