The invention discloses a dry-method pressure-reducing ash discharge device and method. The dry-method pressure-reducing ash discharging device comprises a pressure-reducing unit, a conveying unit anda collecting unit, the pressure-reducing unit comprises a primary pressure reduction equipment inlet special short section, primary pressure reduction equipment, a primary pressure reduction equipment outlet special short section, secondary pressure reduction equipment and a secondary pressure reduction equipment outlet special short section which are communicated in sequence; the secondary pressure reduction equipment outlet special short section is communicated with a solid inlet of a transmitter; the conveying unit comprises a conveying gas pipeline communicated with a gas inlet of the transmitter, the outlet of the transmitter is communicated with a sending buffer tank, and the outlet of the sending buffer tank is communicated with an ash storage tank. Dry-process pressure reduction continuous ash discharging can be achieved by controlling a pressure system, heat can be discharged in time through an arranged gas discharging pipeline, and continuous discharging of high-temperaturedry ash is achieved.