Abstract: Based on the data investigation from sixty-three sample plots in Tongren district of Guizhou province, the effects of site conditions on the growth of poplar plantation clone (I-69) were analyzed. The main results are as follows:The poplar growth varies in different gradients, directions of slope and slope locations. With increase of gradients, DBH, tree height and stand volume decrease gradually. From sunny slope to shady one, it also does, there is a significant difference between sunny slope and shady one, but on the bottom of slope, DBH, tree height and stand volume are higher than those on top of slope. Compared to waste land, the increasement of DBH, tree height and stand volume in the cropland for green was the highest. With increase of soil depth, DBH, tree height and stand volume were all improved. But with increase of soil bulk density, DBH, tree height and stand volume were reduced.