Objective To assess the feasibility of semi-quantitative scoring system for contrast-enhanced ultrasound (CEUS)quantitative analysis's color images in the differential diagnosis of breast nodules.Methods Totally 244 BI-RADS 4 breast solid lesions received CEUS before core needle biopsy or surgical resection were included.A semi-quantitative scoring system for color images of CEUS quantitative analysis were built.The scores were given as follows:1 )Color type and its distribution (0 to 4);2)Color scope (0 to 1 );3)Color margin (0 to 1 );4)Color shape (0 to1 ).The total score for each lesion would be from 0 to 7.And the differenital value between benign and malignant lesions were assessed.Results The total semi-quantitative scores of 102 malignant tumors (5.1 ±1 .7)was significant higher than that of benign lesions (3.34±0.7)(P < 0.05 ).In 102 malignant lesions,the total scores of 81 lesions (79.41 %)were more than 4 points,and in 142 benign lesions,the total scores of 89 lesions (62.67%)were less than 4 points.Depending on the Wilcox rank sum test (Mann-Whitney)analysis,the distribution of total scores between benign and malignant lesions was significant different (P <0.000 1).Total score 4 was selected as the best cutoff,the area under ROC curve was 0.749,on which the sensitivity,specificity and accuracy were 79.4%,62.7% and 69.67%,respectively.Conclusions The semi-quantitative scoring system of CEUS quantitative analysis color images showed good sensitivity but not satisfied specificity and accuracy in differential diagnosis between malignant and benign breast lesions.