Abstract: The paper aims to investigate the longitudinal compressive strength variation of wood in different clones and stem heights of Populus deltoides Marsh. and further broaden its development and utilization. The authors determined and analyzed the growth traits and longitudinal compressive strength of 5 clones 15 years old Populus deltoides Marsh.. The results showed that: the difference of longitudinal compressive strength was significant among different Populus deltoides Marsh. clones; longitudinal compressive strength of different stem heights differed significantly within clones; longitudinal compressive strength of different tested clones all reached above 41 MPa, and that of clone 83 was the largest, which was 48.44 MPa; that of clone 69 was the smallest which also reached 41.06 MPa; the variation tendency of the strength along the tree height was in good agreement with different clones, which was gradually increasing with the tree height increase; however, the strength at different tree heights was different significantly within the same clone; the longitudinal compressive strength of Populus deltoides Marsh. was negatively correlated with DBH and positively correlated with tree height, both were not significant; the correlation coefficient was 0.106 between the strength and the single tree volume, indicating that they had no correlation.