Objective To observe the value of MRI dynamic enhanced imaging and diffusion weighted imaging in the preoperative diagnosis of breast cancer. Methods The clinical data of 98 patients with pathologically confirmed breast cancer admitted to our hospital between June 2014 and September 2016 were selected. All the patients were examined by ultrasonography, DCE-MRI scan, DWI scan, and the results were observed to compare the diagnostic coincidence rate of each inspection technique. Results Confirmed by surgery and pathology, in 98 cases of patients, 41 cases of invasive ductal carcinoma, 16 cases of invasive lobular carcinoma, 9 cases of intraductal carcinoma and 32 cases of ductal carcinoma in situ. DCE-MRI + DWI diagnostic coincidence rate was 92.86%, which was higher than 64.29% of ultrasonography, 72.45% of MRI routine scan and 81.63% of DCE-MRI (P＜0.05), and had no statistical difference with the diagnostic coincidence rate of DWI 86.73% (P＞0.05). Conclusion The value of MRI dynamic enhanced imaging and diffusion weighted imaging in the preoperative diagnosis of breast cancer is high, which can improve the diagnostic coincidence rate, and has guiding significance for surgical treatment.