The invention discloses an automatic horizontal flue-cured tobacco bale loosing device of a tobacco slice making line in a cigarette factory. The automatic horizontal flue-cured tobacco bale loosing device consists of an upper stander (6) and a lower stander (15), wherein a conveyer (23) is arranged at the lower end of the upper stander (6); a clamping cylinder and a push plate (14) are arranged above the conveyer (23); the upper part of the upper stander (6) is connected with mounting bases (10) through a chain and chain connection pins (26); the mounting bases (10) are connected with clamping legs (9); the clamping legs (9) are connected with a clamping leg driving cylinder (11) through connection blocks; the inner sides of the clamping legs (9) are connected with an insertion cutter driving cylinder (18) with an insertion cutter (19); the clamping legs (9) on two sides are connected through a crank sliding block mechanism (21). The automatic horizontal flue-cured tobacco bale loosing device is easier to manufacture, high in production efficiency, low in cost, easy to mount, safer, more stable and more humanized; the smashing rate is lower, and the tobacco back-permeation rate is higher.