In order to improve drilling technology and load characteristics of full-hydraulic vehicle reverse circulation engineering rig,the hydraulic system of GF1500 full-hydraulic vehicle reverse circulation engineering drilling rig was designed.The hydraulic system power head rod rotary speed and pump speed were regulated stepless,the power head feed rate and feed pressure were regulated real-time,the speed and torque output of the system were controlled according to the need to adjust the mud pump hydraulic drilling,to meet various requirements.The field test shows that the hydraulic system is reasonable in design,efficient in energy saving,simple in control and good in maneuverability.