The utility model discloses a downstream compensation system with constant pressure difference. The problem that an executing mechanism of an existing control system cannot be accurately controlled issolved. The device comprises a load-sensitive pump and a plurality of working units, each working unit comprises a variable throttling opening and a valve back compensator; a spring cavity of the valve back compensator is communicated with a feedback oil port of the load sensitive pump; wherein a valve front compensator is arranged at the downstream of an oil outlet of the load-sensitive pump, the valve front compensator is arranged at the upstream of at least one variable throttling port, a control cavity of the valve front compensator is communicated with the oil outlet of the valve front compensator, and a spring cavity of the valve front compensator is communicated with a feedback oil port of the load-sensitive pump. The valve has the characteristics of valve front feedback and valverear feedback, the pressure difference of the valve port is constant, the flow can be distributed in proportion, the flow gain when the opening degree of the valve port is small can be reduced, and the valve is more suitable for low-speed control of a small-flow actuating mechanism.