The present disclosure provides a control method and a control system of a dual clutch transmission for a vehicle. The method includes: a pre-engagement-determining step of determining whether any one of gears has been pre-engaged, by means of a controller; a clutch-moving step of generating an oscillation signal to the release input shaft and increasing a clutch position value of the release input shaft; and a signal-determining step of determining whether the oscillation signal generated to the release input shaft is sensed at the engagement input shaft.