Objective: To investigate the correlation between the peak pressure of contrast agent injection and tubal patency during real-time three-dimensional hysterosalpingo-contrast sonography. Methods: Seventy female patients who underwent real-time three-dimensional hysterosalpingo-contrast sonography of uterine and oviduct in the department of ultrasound medicine in our hospital were selected to measure the peak pressure in the examination process through the pressure injection device of contrast agent, to compare the pressure differences of different obturability patency degree of oviduct, and to draw a ROC curve to determine the optimal cut-off value of the peak pressure. Results: According to the different patency degree of fallopian tubes, the contrast results were divided into three groups: bilateral tubes unobstructed group, unilateral tube lesioned group and bilateral tubes lesioned group. The peak pressures of the three groups were (34.69±9.30) KPa, (52.71±18.55) KPa and (73.88±11.01) KPa, respectively. The area under the peak pressure ROC curve (AUC) of the "unilateral tube lesioned group" and "bilateral tubes lesioned group" was 0.785, the optimal cut-off value of the peak pressure was 51.90KPa, the area under the peak pressure ROC curve (AUC) of the "unilateral tube lesioned group" and "bilateral tubes lesioned group" was 0.851, and the optimal cut-off value of the peak pressure was 73.50KPa. Conclusion: The peak pressure of contrast agent injection in RT-3D-HyCoSy can be used as a quantitative index to deduce the patency degree of oviduct. There is a correlation between the peak pressure and the tubal patency.