Abstract: To implement the high carrier communication, wideband microwave synthesis of the local oscillator has become the main way of design. Due to the influence of the YTO (YIG Tuning Oscillator) hysteresis characteristics and non-linear characteristics, the normal manual calibration may cause the PLL unlock at the process of capturing. Based on the basic principles of single phase-locked loop and the YIG oscillator tunable characteristics, a self-calibration YTO single PLL(phase-locked loop) has been designed, it can not only avoid loop unlock caused by YTO hysteresis characteristics and non-linear characteristics, but also decreases the loop capture time; In addition, the introduction of the feedback loop in the mixer part reduces the amount of loop phase noise deterioration. Analysis for the final measurement of calibration curve shows that the self-calibration function is very necessarily in the YTO PLL design.