The invention discloses a hydraulic balance automatic control system for a reciprocating type boosting water injection pump and an adjusting method of the system. The system comprises a suction pressure detection device, a balance pressure detection device and a discharge pressure detection device which are mounted on a reciprocating type boosting water injection pump pipeline, wherein a regulating valve used for regulating suction pressure or balance pressure is mounted between the balance pressure detection device and the discharge pressure detection device. By means of monitoring for the suction pressure, the balance pressure and discharge pressure in the pump body, change of the pressure in the pipeline can be acquired at any time, by means of timely regulation for the regulating valvelocation, the hydraulic balance system enters a balance mode again, the phenomenon of the hydraulic balance system imbalance of the reciprocating type boosting water injection pump due to various reasons is effectively eliminated, besides, when the hydraulic imbalance condition occurs, the balance relation can be established again timely and effectively, the continuous operation of the equipmentis guaranteed, the failure rate caused by abnormal wear of the equipment is eliminated, and long-term stable operation of the equipment is realized.