Abstract: The study on the stem seconday xylem of Sambucus williamsii, reveals there are vassel elements, fibretracheid, septate fibres and wood fibre in it. The wood belongs to ring porous wood. The ray is hetergeneous rayⅡ.The perforation plate is simple perforation. There are 5 types vassel elements with different location and number of simple perforation on vassel element wall: only one end has a simple perforation plate and the other end has helical thickening; only one end has two simple perforations plates and the other end has helical thickening; each end has a simple type, with helical thickening on the wall; each end has a simple type, with reticular thickening on the wall ;there are 3 simple perforation plates,and one end has two simple types and the other end has one simple type, with reticular thickening.