Objective:To explore the diagnostic efficacy of percutaneous lymphatic contrast ultrasound (LCEUS) combined with clinicopathological features in the diagnosis of breast cancer sentinel lymph node (SLN).Methods:A total of 135 breast cancer patients who underwent sentinel lymph node biopsy and axillary lymph node radical resection were prospectively collected in the Affiliated Hospital of Nanjing University of Chinese Medicine from July 2018 to June 2021, and the breast masses and SLNs were evaluated by routine ultrasound, contrast-enhanced ultrasound and LCEUS within one week before surgery. The surgeons recorded the patients′ clinical characteristics before surgeries, and the pathology of the masses and SLNs were recorded after surgeries. Univariate analysis and multivariate Logistic regression analysis were used to explore the correlation between ultrasound clinicopathological features of breast cancer and SLN metastasis, then to establish a model, and evaluate the diagnostic efficacy of the model.Results:Univariate analysis showed that SLN metastasis of breast cancer was associated with age, axillary palpation of enlarged lymph nodes, pathological type of mass, clear hilum of lymph nodes, cortical thickening of lymph nodes, marginal blood flow in lymph nodes, and the appearances of LCEUS(all P<0.05). Multivariate Logistic regression analysis showed age, palpation of axillary lymph nodes and the appearances of LCEUS were independent predictors of SLN properties, the OR values were 6.90 ( P=0.030), 16.06 ( P<0.001) and 12.71 ( P<0.001), respectively. The regression equation was Logit(P)=0.887+ 1.932× axillary lymph node palpation + 2.776× marginal blood flow + 2.542×LCEUS. Conclusions:LCEUS combined with marginal blood flow in lymph nodes and palpation of axillary lymph nodes can help to determine the SLN state.