Objective:To analyze the value of color Doppler flow imaging (CDFI) in evaluating effects of neoadjuvant chemotherapy (NAC) for breast cancer.Methods:100 patients with breast cancer who underwent surgery after NAC in Cancer Hospital of Inner Mongolia Autonomous Region from January 2018 to April 2019 were selected for retrospective analysis. According to effects of chemotherapy, they were divided into effective group and ineffective group. The changes in lesion size, ultrasound findings, grade of blood flow in lesions, resistance index (RI) and peak systolic velocity (PSV) before and after NAC were compared between the two groups.Results:The length, width, thickness and volume of masses in effective group after NAC [(2.03±0.24)cm, (1.69±0.24)cm, (1.06±0.14)cm, (3.64±0.39)cm 3] were smaller than those before NAC [(3.40±0.36)cm, (2.35± 0.26)cm, (1.78±0.19)cm, (14.24±1.53)cm 3] and those in ineffective group after NAC [(3.31±0.34)cm, (2.36±0.27)cm, (1.76±0.19)cm, (14.19±1.42)cm 3] ( P<0.05). After NAC, the the proportion of regular shape, clear boundary, more internal echo, and no abnormal posterior echo in effective group was statistically significant ( P<0.05), but there was no significant change in the ineffective group ( P>0.05). The proportion of clear boundary and excessive internal echo in the effective group was higher than that in the ineffective group ( P<0.05); the blood flow grade of the effective group after NAC was lower than that of the ineffective group ( P<0.05) After NAC, the RI (0.54±0.06) in effective group was lower than that in ineffective group (0.65±0.08) ( P<0.05), and there was no significant difference in PSV between the two groups ( P>0.05). Conclusions:The value of CDFI is high in evaluating NAC effect on patients with breast cancer. It can effectively measure and judge lesion size and blood flow changes, and provide basis for clinical curative effect evaluation.