The utility model relates to the technical field of damp-proof and dry maintaining devices, in particular to a building underground structure damp-proof and dry maintaining device which comprises a
basement wall body, the inner wall of the wall body is coated with a damp-proof
coating to reduce the damp risk of the wall body, and a damp-proof layer is fixedly arranged on the outer side of the wall body to effectively prevent underground water or rainwater from leaking. Meanwhile, the interior of the
basement is kept dry and comfortable, a heat preservation layer is fixedly arranged on one side of the damp-proof layer, a waterproof and vapor-proof layer is arranged on one side of the heat preservation layer,
moisture and
water vapor are prevented from entering the
basement through dual protection, an empty layer and a pipeline are arranged between the heat preservation layer and the waterproof and vapor-proof layer, and
moisture is allowed to enter the interior of the pipeline from the empty layer; the water-proof and vapor-proof layer is used for pumping water and discharging the water to the outside through a negative pressure pumping device, dry air is introduced, the
humidity of the empty layer and the wall body is reduced, the dry state is maintained, a flow guide plate used for preliminary
moisture prevention is fixedly arranged on one side of the water-proof and vapor-proof layer, and a fixing box used for collecting permeated water is clamped to the bottom of the flow guide plate.