To investigate the ultrasonographic characteristics of senile invasive ductal carcinoma of breast and its correlation with molecular typing.

127 elderly patients with invasive ductal carcinoma of breast from July 2020 to July 2022 were retrospectively analyzed. All subjects underwent breast ultrasound examination within 2 weeks before surgery. Ultrasound images were analyzed by 2 senior sonographers in our hospital，including lesion diameter，shape，boundary，burr，lobule，posterior echo，and blood flow. Molecular types include luminal A，luminal B，HER-2 overexpression and basal-like. Statistical software SPSS 23.0 was used for processing，and counting data were expressed as percentage/case number by χ² test. P<0.05 was statistically significant.

In the ultrasonic characteristics of elderly patients，most lesions were less than 2cm in diameter，irregular in shape，blurred in boundary，burr and lobed，attenuated in rear echo and not rich in blood flow. Molecular typing included luminal A type in 13 cases，luminal B type in 72 cases，HER-2 overexpression type in 27 cases and basal-like type in 15 cases. The factors related to molecular classification of invasive ductal carcinoma of breast included lesion diameter，morphology，boundary，burr and posterior echo（P<0.05），but there was no significant correlation with lobular and blood flow（P>0.05）.

The ultrasonic characteristics of senile invasive ductal carcinoma of breast were mainly irregular shape，blurred boundary，burr，lobule and attenuation of posterior echo，and the molecular classification was significantly correlated with the focus diameter，shape，boundary，burr and posterior echo.