The invention discloses a banana stem smashing device, and relates to the technical field of agriculture. The banana stem smashing device can directionally and efficiently smash banana stems. The banana stem smashing device comprises a cutter disc set, a lifting mechanism for lifting the cutter disc set, a guiding mechanism, and a first connecting rod connected with the cutter disc set and the guiding mechanism. A certain included angle is formed between the cutter disc set and the forward motion direction of the banana stem smashing device. The lifting mechanism comprises first erected fixing frames. The upper end of each first fixing frame is hinged to a first stretchable rod extending downwards. The lower end of each first fixing frame is hinged to a second connecting rod matched with the corresponding first stretchable rod. The end of each stretchable rod is hinged to the middle of the corresponding second connecting rod. The tail of each second connecting rod is hinged to a first connecting frame correspondingly connected with the cutter disc set. The guiding mechanism comprises a guiding wheel, a guiding rod and a guiding sleeve arranged on the guiding rod in a sleeving mode. The guiding sleeve is composed of two symmetric sleeve pieces. The guiding wheel and the guiding rod are connected. The banana stem smashing device is applied to banana stem smashing and returning.