Objective: To study the application of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) parameters in the diagnosis of breast cancer and its relationship with the expression of immunohistochemical indicators. Methods: A retrospective analysis of 70 cases of suspected breast cancer admitted in our hospital from December 2019 to December 2020 was conducted. The Philips Ingenia 3 T superconducting MRI scanner and the mammary phased coils were used to detect the apparent diffusion coefficient (ADC) value, slow diffusion coefficient value (D value), fast diffusion coefficient value (D* value) and perfusion fraction value (f value) by imaging sequence setting. Meanwhile, the indexes of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 were detected. Results: Pathological examinations diagnosed 22 cases of benign tumors and 48 cases of malignant tumors; 54 cases were ER positive and 16 cases were negative; 50 cases were PR positive and 20 cases were negative; 55 cases had high expression of Ki-67 and 15 cases had low expression; 27 cases were positive for HER-2, 43 cases were negative. The ADC value, D value and D* value of malignant tumor patients were lower than those of benign tumor patients, and the f value was higher than that of malignant tumor patients, and the difference was statistically significant (P<0.05). There was no significant difference in ADC value, D value, D* value and f value between ER-negative and positive patients, PR-negative and positive patients, and HER-2-negative and positive patients (P>0.05). There was no significant difference in the D* value and f value of the expressing patients (P>0.05). The ADC and D values of patients with high Ki-67 expression were lower than those with low expression, and the difference was statistically significant (P<0.05). ER, PR, HER-2 had no correlation with ADC, D, D*, f values respectively (P>0.05), and Ki-67 had no correlation with D*, f values (P>0.05), but was positively correlated with ADC and D values (P<0.05). Conclusion: IVIM-DWI quantitative parameters ADC, D, D* and F values can provide a valuable basis for the qualitative diagnosis of breast cancer. There are statistical differences between the parameters ADC and D in the patients with high and low expression of Ki-67 in breast cancer, which can provide a reference for predicting the expression of Ki-67.