The invention discloses a paraffin slicing method of tree stem tissue, and belongs to the technical field of plant microscopic structure slicing. The paraffin slicing method of the tree stem tissue comprises the operations of tissue fixing, primary softening, dehydration, transparency, waxing, embedding, secondary softening, slicing, slice folding, slice gluing, slicing roasting, dewaxing, rehydration, dyeing, slice sealing and the like, wherein the addition of softening treatment can solve the problem that phloem, a forming layer and xylem in the stem tissue are easy to break in the slicing process due to inconsistent hardnesses. The softening treatment comprises the steps of firstly after the tissue is fixed, adding the operation of using ethyl alcohol/glycerinum mixed liquor to soften the tissue; secondly after embedding and coarse machining, adding the operation of using warm water to soak so as to soften the tissue to be sliced. Experiments demonstrate that a softened tissue can lower probability that the stem tissue is easy to break during slicing, and improve slicing success rate.