【Abstract】 Objective To investigate the relationships between histologic grade and molecular subtype of invasive breast cancer. Methods A retrospective study was performed on 128 cases of definitely diagnosed invasive breast carcinomas of our department from 2017 to 2019. All the HE slices and IHC slices of each case are reviewed, then each tumor was graded and put into molecular subtypes at the same time, according to the Nottingham grading system and molecular classification model recommend by WHO (2019). The data were statistically analyzed using spss26.0 software. Results According to the calculations，we have the ideas that the histologic grade and molecular subtype of a breast cancer are dependent on each other（χ2=44.8，P＜0.001）,furthermore there very likely exists a moderate positive correlation between them(r=0.49，P＜0.001).Conclusion Histological grade and molecular typing of invasive breast cancer have a certain degree of correlation and a certain degree of difference in reflecting the biological information of cancer. The histological grading and molecular typing of breast cancer reflect the gene expression information of breast cancer to some extent, which not only has certain theoretical significance, but also has positive clinical and pathological significance. In the process of diagnosis, the two complement each other and confirm each other, so as to ensure the accuracy of pathological diagnosis and benefit the implementation of individualized treatment plan for breast cancer.