Abstract: Objective To analyze the differential diagnosis and misdiagnosis of benign and malignant breast cancer by shear wave elastography. Methods A total of 146 patients with microscopic lesions of the breast who were treated in our hospital from January 2017 to January 2019 were enrolled, including 48 malignant tumors and 98 benign tumors. All patients underwent shear wave elastography and ultrasonography. The diagnostic efficacy of two methods for benign and malignant breast lesions was compared. Univariate and multivariate logistic regression models were used to analyze the misdiagnostic factors affecting small breast lesions by shear wave elastography. Results The diagnostic efficiency of shear wave elastography for breast small lesions was higher than that of B-ultrasound(all P<0.05). Univariate and multivariate logistic regression analysis showed that lesions<8 mm(OR=11.284, P=0.006) and carcinoma in situ(OR=8.402, P=0.044) were independent risk factors leading to false negative test results; distance from the skin>9 mm(OR=8.116, P=0.006), distance from the shallow chest wall<2 mm(OR=11.831, P=0.002), breast thickness>24 mm(OR=10.032, P=0.006) were independent risk factors leading to false positive test results. Conclusion Shear wave elastography can qualitatively and quantitatively analyze the benign and malignant lesions of breast microscopic lesions, and has high diagnostic efficiency, but there are still some factors leading to misdiagnosis.