Objective To evaluate the value of sterotactic mammorgraphy core needle biopsy in the diagnosis of nonpalable breast lesion. Methods 32 cases in this study were diagnosed by SMCNB,of whem,21 cases were operated on.Pathologic findigs of the tissues through SMCNB were compared with those of tissues by operation. Results Accuracy of diagnosis from SMCNB was 95%,sensitivity 80%,and specificity 100%.False negative result was found in 1 case.No false positive result occurred. Conclusions SMCNB is a simple and less invasive procedure with accurate location.It is valuable in the diagnosis of nonpalpable breast lesions.