The invention relates to an adjustable discharging pipe device for a preheater cabin. The adjustable discharging pipe device comprises the preheater cabin, a fixed discharging pipe, a fixed horn opening, a material cabin and an adjustable outer sleeve, wherein the outer sleeve is arranged outside the fixed discharging pipe in a sleeving mode; the center lines of the fixed discharging pipe, the fixed horn opening and the outer sleeve are enabled to coincide with each other; meanwhile, trunnions are respectively arranged on an outer arm of the outer sleeve and an outer arm of the fixed discharging pipe, and the outer sleeve and the fixed discharging pipe are connected through steel wire ropes arranged on the trunnions. According to the adjustable discharging pipe device disclosed by the invention, the adjustable outer sleeve is arranged outside of the fixed discharging pipe, and the expansion length of the outer sleeve extending into the preheater cabin is utilized to increase or reducethe height of material layers in the preheater cabin; thus, the purpose of aiming at required preheating time of different limestone mine materials in the preheater cabin is achieved; finally, the problem of burst of the different limestone mine materials in the preheater cabin is solved; quality and yield of lime are practically improved.