In order to improve the ditch depth precision of corn no-tillage seeder, this research combined infrared distance measure and spin encoding speed with speed change hydraulic controlled system, canceled complicated Parallel four-bar trenching profiling wheel groove depth control device of traditional ground profiling mechanism, and designed a system composed by ground information collecting, information transmission processing and hydraulic profiling controlling, which is an automation system to control ditch depth with multiple probe point infrared distance sensor height measurement variable speed hydraulic control mode.The system of ground information collection could collection working speed of seeder and information of elevation changes, which including speed information collection agencies and elevation information acquisition components.This could be get the variation of hydraulic profiling mechanism according calculated these information, so it has the function of probing the ground ditched.The instruction of speed information collection could make speed measurement sensor synchronously rotating according transmission by transmission gear of seeder, and then make the Point frequency signal transferred to the system of information transmission processing by the manner of data lines connect.This could collection the spreed of seeder in real time.The system of elevation information collection was constituted by a number of infrared distance sensor installed in the connecting rods of furrow opener, connected with information transmission processing system by data lines.It could measured the change of ground height by triangulation method.The information transmission processing system was composed of Arduino: a hardware of date processing and control, data transmission line and signal monitor.The function of this system was transfer and calculate different signals of many components to a unified signal.It could plays an important role of central control, according processing and outputting control signals of ground information come across from ground information collection system, then control the piston displacement of hydraulic profiling controlling system.After built-in program of Arduino processing the information of speed and the elevation changes, outputted control signals could controlling the hydraulic profiling institution.The hydraulic profiling controlling system made up with reliefvalve,hydraulicpump,electrohydraulic proportional reversing valve,double-acting hydraulic cylinder, fueltank, accumulatorandpipe accessory.Electrohydraulic proportional reversing valve could control the flow and direction of hydraulic oil entered into double-acting hydraulic cylinder,so it could be make the piston to motion by change the direction and flow.It could completed the mask of the variable piston displacement in unit time, by control the depth of furrow opener, then make a uniform depth of ditch.When the height of ground changed, elevation information collection institution transfer collected ground variation to Arduino, then Arduino calculated highly variable displacement of furrow opener in unit time combining with the spreed of seeder, Outputted the control signal to electrohydraulic proportional reversing valve which in the hydraulic profiling institution, electrohydraulic proportional reversing valve control hydraulic cylinder piston rod and to carry on the corresponding movement speed corresponding variables.The ditch depth precision was taken as an index to carried out a aboratory room test.The resulted indicated that precision of the ditch depth automatic control system of com no-tillage seeder is 10 mm ± 5 mm, this result illustrate the automatic control system significantly better than type of contour wheel Trenching depth control system, and showed better adaptability.