A jitter measurement circuit and a method for calibrating the jitter measurement circuit are disclosed. The jitter measurement circuit includes a synchronous dual-phase detector and a decision circuit. In a test mode, a probability distribution function (PDF) of the jitter of a clock signal output by a circuit under test is obtained. In a calibration mode, a random clock, which is externally generated or generated by a free-run oscillator in the circuit under test, is used to calibrate the synchronous dual-phase detector. The decision circuit performs logic operations, data latching and counting on a phase relationship detected by the synchronous dual-phase detector in order to obtain a counting value and a PDF relative to the jitter of the clock signal.