A control circuit of delay lock loop and a control method thereof are provided. The control circuit includes a power status detector, a voltage comparator, an enable signal generator and a control signal generator. The power status detector detects a transition edge of a clock enable signal to generate a trigger signal corresponding to a variation of an operation power. The voltage comparator compares the operation power with a reference voltage to generate a comparison result. The enable signal generator sets an enable signal to an active state according to the trigger signal and sets the enable signal to a non-active state according to the comparison result. The control signal generator outputs a control clock to generate a control signal when the enable signal is in the active state.