ObjectiveTo investigate the value of computer-aided detection（CAD）assisted automated breast ultrasound system（ABUS）for malignant breast lesions diagnosis in doctors with different seniority.MethodsOf the 1452 breast cases

270 cases were malignant with a total of 282 lesions

674 cases were benign with a total of 695 lesions

and 508 were negative.The diagnostic sensitivity

specificity

area under the ROC curve

and average reading time were compared among 6 doctors（3 junior and 3 senior）before and after using the CAD system.Results Before the application of CAD system

the sensitivity of junior and senior doctors were 87% and 93%

respectively

and both increased to 94% after using CAD.There was significant difference in the sensitivity of junior doctors before and after using CAD（P<0.05）

while no statistic difference was found in the senior doctors before and after using CAD.Diagnostic specificity of the 6 doctors decreased slightly before and after using the CAD system

but the difference was not significant.The diagnostic accuracy of junior doctors has improved

and the area under the curve has increased from 0.85 to 0.89

the differences was statistically significant（P<0.05）. The area under the curve has increased from 0.91 to 0.92 in senior doctors after using CAD

but there was no significant difference.The mean reading time of all doctors after using CAD was prolonged to varying degrees

and the difference was statistically significant（P<0.05）.Conclusion Although the average reading time after using CAD has been extended

within the acceptable range

the reading mode of ABUS combined with CAD can greatly improve the accuracy and sensitivity of ultrasonic doctors in diagnosing malignant breast lesions

and it is more helpful to junior doctors.