The invention provides a ceramic sintering furnace. The ceramic sintering furnace comprises a furnace body, an inner liner layer, cranks and resetting springs. The inner liner layer is arranged on theinner side of the furnace body, and the cranks are installed on the outer side of the furnace body. First bevel gears are installed on the cranks, and second bevel gears are connected to the outer sides of the first bevel gears. Vertical shafts are installed on the second bevel gears, and the second bevel gears and the inner liner layer are connected with each other through the vertical shafts. Asealed sleeve is installed on support rods and located on the inner side of a valve pipe. Besides, second ventilation holes are formed in the sealed sleeve. According to the ceramic sintering furnace, when air pressure inside the furnace is too large, the sealed sleeve is jacked by hot air till the second ventilation holes in the sealed sleeve are aligned with first ventilation holes in the valvepipe, thus in-furnace pressure is conveniently relieved; and when decompression is finished, the sealed sleeve is pushed by the resetting springs to move downwards till the second ventilation holes and the first ventilation holes are dislocated, and thus sealing is achieved.