The utility model relates to a negative pressure ash conveying system of thermal power plant and malleation ash conveying system combine running device, including the economizer, the lower part of economizer is provided with ash falling bucket, and ash falling bucket's export all links to each other with mixing box through the pipeline, and mixing box's lower part is connected with economizer sending tank through the blanking pipe, economizer sending tank's lower part is provided with the discharge gate, and economizer sending tank is connected with thick grey storehouse, and thick grey storehouse and thin grey storehouse link to each other, and the upper portion in thick grey storehouse is provided with thick grey storehouse sack cleaner, and the upper portion in thin grey storehouse is provided with thin grey storehouse sack cleaner, compressed -air storage tank is connected with economizer sending tank to owner that row are connected mixes the valve and is connected through the preceding back with bleeder valve of pipeline from the pneumatic door that admits air with the vice valve that mixes, compressed -air storage tank's lower part is provided with the compressed -air storage tank (air) intake valve, its ability disinvestment, the compatibility and the security of the operation of improvement system.