A method of controlling a lock pin of a CVVT (continuous variable valve timing) system is provided. The method includes an oil supply operation of operating a spool of a valve bolt by means of oil drawn into the CVVT system and supplying the oil to the lock pin and a switching valve. The method further includes a switching-valve opening operation of opening the switching valve by means of pressure of the oil supplied in the oil supply operation, and a lock-pin releasing operation of supplying oil to a chamber when the switching valve opens and releasing the lock-pin when there is no difference in oil pressure between an advanced chamber and a retracted chamber.