Abstract: When planting poplar trees, two kinds of cultivating techniques of artificial pruning and dipping roots into chemical preparation were used to control the poplar canker, Dothiorella gregaria Sacc.. The two methods are: ①all of the lateral branches were cut off and roots were dipped into 100ppm liquid of ABT-3 rooting powder; ②all of the lateral branches and 1/3 of the tip of one year-old trunks were cut off and roots were dipped into 100ppm liquid of ABT-3 rooting powder. As a result of adopting the two techniques, the leaves surface of the young trees were reduced; the number and length of roots were increased and the time of rooting was moved up. Thus, the water contents in both treatments were higher than that in the control. Furthermore, their resistance to the disease was raised. The surviving rate of the planted trees increased by 70%～90%;the control effect was 80%～90%.