The present invention provides a buried depth of phreatic water level inducement technical method for the root system growth of the young seedling of desert plants. A constructed netting testing tank consists of tank wall, column piers, a steel wire netting and a water injection pipe and is filled with stones and earthwork, wherein, the tank wall is ensured to be watertight; the bottom of the tank is distributed with the column piers to ensure that the ground water can flow; the upside of the column piers is laid with the steel wire netting; the upside of the steel wire netting is laid with the stones firstly and then is filled with the earthwork layer by layer; a ground water table control testing area which has the thicknesses of earth layers of 100cm, 150cm, 200cm, 250cm and 300cm respectively is arranged to ensure that the ground water table is always kept at 45 to 55cm. The technical method testifies the relation between the working depth of the vertical root of the young seedling and the growth speed of the vertical root under the condition of different buried depths of phreatic water level, testifies the changing characteristic of the root system state of the young seedlingalong with the change of the ground water level and the water content of soil, testifies the distribution rule of the quality and the surface area of the root system of the young seedling in soil space and testifies the biomass allocation trend of the young seedling under the condition of different buried depths of phreatic water level. The technical method has reasonable design and strong operability. The testing tank can be molded by casting concrete or be made by laying with waterproof material in a concrete-brick structure.