The utility model aims to design a coal pulverizer hot air duct seals locking device, it is by the pulley, the support, the slide, the fixed column, the lock, it constitutes to seal the board, set up the slide mouth at hot air duct, and a support, the slide is established in hot air duct the inner and is sealed the board, the fixed column is established to the slide other end, the fixed orifices is established to the fixed column, the support is divided into to the slide, establish the pulley on the support, the slide can slide after the pulley is gone forward, the lock is established to hot air duct outer wall slide mouth top, the lockhole is established to the lock, when hot air duct inner sealing hot air port is shifted onto to the slide, the lockhole of lock setting can pass from the fixed orifices, and can be at the sino -Canada lock of lockhole, when overhauing the coal pulverizer, close cold and hot wind regulating plate, cold and hot wind isolation door, the slide, add the lock by the maintainer at the lockhole, with the safety of guaranteeing the maintainer.