Abstract:The wood structure of Syringa oblata var. giradii Rehd. grown on the north side of Taibai Mountain varied with the increasing altitude: the width of growth ring, the length of vessel member, the vessel diameter, the length and width of fibretracheid and the ray height gradually increased with the altitude; the frequency of vessel, the frequency of ray and the frequency of solitary vessels decreased; the vessel and fibretracheid walls grew thinner. The spiral thickenings of the vessel wall and the fibre-tracheid wall in the lower altitude are more evident and them gradually obscure.