A circuit for calibrating a data control signal includes a time-delay compensation circuit and a voltage-control delay circuit. The time-delay compensation circuit receives two complementary signals and a direct current voltage which has two voltage cross points with the two complementary signals respectively, and outputs a control voltage according to a time difference between the two voltage cross points. The voltage-control delay circuit delays a data control signal for a predetermined time according to the control voltage, thereby eliminating signal skew between the data control signal and a data signal.