This technology involves the field of environmental protection, is a bag filter bypass protection structure, which includes dust and bypass valve, wherein the bypass valve outlet and inlet filter Feng Yan Road connection, bypass bypass valve outlet and filter out Feng Yan channel connection, set the shut-off valve between the filter outlet filter chamber and the Wind and Smoke Road, the bypass valve and shut-off valves are chain control. The technique is simple structure, easy maintenance, save space, save steel consumption, while ensuring manufacturing precision.