The invention discloses a layer-combustion combustion device ascending and descending vertically. The layer-combustion combustion device comprises a combustion chamber, a fuel cavity, a fire grate and collection tanks. The fuel cavity is formed in the combustion chamber and located on the upper portion of the combustion chamber, and a certain gap is formed between the fuel cavity and the combustion chamber. The fire grate is arranged at the bottom of the fuel cavity and comprises an air distribution plate, a motor and a push threaded rod. The motor can drive the push threaded rod, so that the air distribution plate moves upwards along the fuel cavity. The fire grate is further provided with an air supply outlet. The air supply outlet is arranged to communicate with an air blower, so that after passing through the air distribution plate, air is sent into the fuel cavity. The collection tanks are arranged between the bottom of the fuel cavity and the combustion chamber and used for collecting ash discharged after fuel is combusted. The layer-combustion combustion device has the beneficial effects of being compact in structure, low in metal consumption, easy to adjust, not prone to burning-out, great in heat load adaptive capacity, few in heat loss and the like.