Transvaginal 4-D hysterosalpingo-contrast sonography with SonoVue (TV 4-D HyCoSy) is the preferred imaging method for evaluating tubal patency. However, venous intravasation in 4-D HyCoSy may affect the diagnosis of tubal patency. The objective of this study was to analyze influencing factors of venous intravasation during TV 4-D HyCoSy. This study included 643 infertile patients who underwent TV 4-D HyCoSy. We analyzed the relationship between the incidence of venous intravasation and patients' basic clinical data, endometrial thickness, inspection timing (clean day of menstruation) and tubal patency. A total of 169 (26.28%) patients exhibited intravasation during TV 4-D HyCoSy. The following are risk factors for venous intravation: secondary infertility, type C + C, type B + C and type B + B in bilateral fallopian tubal patency grouping; endometrial thickness ≤5.45 mm; and taking TV 4-D HyCoSy after menstruation ≤6 d. Infertility duration, intrauterine lesions, a history of pelvic inflammatory disease and a history of pelvic surgery were uncorrelated with venous intravasation. To reduce the incidence of venous intravasation, TV 4-D HyCoSy should be performed 7-10 d after menstruation or when endometrial thickness is thicker than 5.45 mm.