The variations in fiber length, specific gravity and comp0sition content of three Italian poplars clones for pulpwood Tvere reported in this pa-per. Ir radial direction,fiber length,specific gravity and cellulose content of wood increased from pith outward, and level off after 8 to 10 years old;lignin and pentosan content decreased from pith to bark, and level off after 10 years old. The radial variation of fiber length-width ratio was similar to the patten of fiber length.Along the stem height,fiber Iength decreased gradually and specific gravity increased from base upward.Based on radial variation of fiber length and specific gravity at 1.3 m height within trees,the duration of juvenile peroid was determined about 8 years old. Its lower specific gravity is improved by tree breeding. Based on variations in the whole tree’s fiber length,specific gravity,chemi-cal composit and growth property,harvesting of Italian populars for pulp-wood at 8 to 9 years old was good.