A hydraulic control system for a construction machine comprising a hydraulic actuator (11) that drives an arm (51), a meter-out channel (34, 35) through which hydraulic fluid discharged from the hydraulic actuator flows, a variable restrictor (23a, 23b) provided in the meter-out channel (34, 35), an operating device (5), and a controller (45) that controls an opening area of the variable restrictor is equipped with a posture calculation unit (45a) that calculates an angle made by the arm (51) with respect to a horizontal direction, a meter-out opening area calculation unit (45b) that calculates the opening area of the variable restrictor (23a, 23b) based on the angle made by the arm (51) with respect to the horizontal direction and a time rate of change of the angle, and a meter-out control unit (45c) that outputs a command signal to a solenoid valve (44) used for adjusting the opening area of the variable restrictor (23a, 23b), based on the opening area of the variable restrictor calculated by the meter-out
