Abstract: Objective To investigate the accuracy rate of fine needle aspiration biopsy(FNAB) for breast mass in our hospital and discuss the reasons of false diagnosis. Methods The results of 820 fine needle aspiration biopsy of breast mass were analyzed.Four hundred and ninty-eight cases were taken for histopathological examination;the results of FNAB and histopathology were compared. Results The 820 cases included 583 cases of benign tumor and 237 cases of malignant tumor.The according rate of FNAB and histopathology was 95. 78 %. Conclusion 　The examination of fine needle aspiration biopsy for breast mass has high accuracy rate. It is helpful to establishing the t reatment program for clinical doctors.