Objective To explore the value of MRI enhanced scan and apparent diffusion coefficient (ADC) in evaluating the curative effect of chemotherapy in breast cancer. Methods 50 cases of patients with breast cancer treated with neoadjuvant chemotherapy in our hospital from January 2013 to January 2015 were studied. All patients underwent MRI before chemotherapy, 1 cycle of chemotherapy later and after whole course of chemotherapy, including routine scan, enhanced scan and diffusion weighted imaging (DWI). The maximum axial diameter of tumor, early enhancement rate and changes of ADC values were compared before and after chemotherapy. According to the pathological curative effect, the patients were divided into complete remission group and incomplete remission group. The tumor regression rate at the end of the whole course of chemotherapy was compared between the 2 groups. For the related parameters after whole course of chemotherapy, Spearman correlation analysis was performed. Results After whole course of chemotherapy, the maximum axial diameters, early enhancement rates at the 1st min, 2nd min and 3rd min were significantly lower than those before chemotherapy while ADCmin and ADCmean increased significantly (P<0.05). The tumor regression rate in the complete remission group [(0.690±0.193)] was significantly greater than that in the incomplete remission group [(0.409±0.338)] (P<0.05). The tumor regression rate was significantly correlated with the maximum axial diameter and early enhancement rate (P<0.05) but was not correlated with ADC value (P>0.05). When the tumor regression rate was over 54.45%, the sensitivity and specificity in diagnosis of complete remission were 84.5% and 75% respectively. Conclusion ADC value of DWI has great value in early response to neoadjuvant chemotherapy for breast cancer. It is one of the important indicators to predict the curative effect by MRI enhanced scan and DWI sequence observing tumor regression rate