As a gradual environmental geological disaster, soil salinization severely restricts the human life and the development of social economy, the improvement of saline alkali soil and the development & utilization of brackish water have become the hotspot in the world. Open channel, subsurface drainage and subsurface drainage combined with large diameter vertical shaft and alkali resistant plant were used for saline alkali soil improvement, but open channel and buried underground pipe have great damage to ground surface with disadvantages of limited water displacement and applicable depth, long plant improvement cycle and being time-consuming. By horizontal directional drilling (HDD), screen pipe can be horizontally or nearly horizontally installed in the aquifer and be laid perpendicular to the aquifer flow in a long distance. Compared with the conventional tube well drilling, there are advantages of larger water yield, low cost and small impact on the environment. The engineering example proves that this construction technology is ideal for saline alkali soil improvement, development