A hydraulic control system for a power train including a shift speed mechanism, a frictional element for switching a shift characteristic of the shift speed mechanism, a hydraulic control mechanism for controlling a hydraulic pressure, a target shift time setting device for setting a target shift time based on an input speed difference of the shift speed mechanism through the shift operation and an input torque introduced to the shift speed mechanism, an angular acceleration calculator for calculating an angular acceleration of an input member of the shift speed mechanism based on the target shift time obtained through the target shift time setting device and the input speed change of the shift speed mechanism through the shift operation, an inertia hydraulic pressure setting device for setting an inertia hydraulic pressure for coping with a moment force due to a moment of inertia of a power transmitting system to the shift speed mechanism based on the angular acceleration of the input member of the shift speed mechanism obtained through the angular acceleration calculator, an input torque pressure setting device for setting an input torque hydraulic pressure corresponding to the input torque introduced to the shift speed mechanism based on the input torque and, a target pressure setting device for setting a final target hydraulic pressure for the hydraulic control mechanism based on the inertia hydraulic pressure and the input torque hydraulic pressure. The shift shock is effectively suppressed.