A method of adjusting clutch characteristics of a Double Clutch Transmission (DCT) vehicle may include determining whether gear shifting has been initiated, updating a T-S curve of a release-side clutch by a transmission torque that is determined using an equation of motion of an engine and a clutch, when a condition in which a difference between an engine speed and a speed of a release-side input shaft is satisfied to be above a first predetermined reference value during a first reference period of time when the gear shifting is determined to have been initiated, and when a torque handover has not been initiated, updating the T-S curve of a connection-side clutch by the transmission torque that has been determined using the equation of motion during a period of time from completion of torque handover to completion of the shifting of gears.