ObjectiveTo study the detection methods of micrometastasis in sentinel lymph nodes (SLN) and their clinical significance. MethodsFifty women with breast carcinoma were included. SLN in fifty breast carcinoma was identified by using methylene blue staining to detect and remove them for routine hematoxylin and eosin stain and histological exam. All negative SLNs were examined by serial section (SS) with the section interval of 250 μm and HE stain for microscopic examination and immunohistochemical (IHC) exam was performed with CK19 monoclonal antibody. Then the above three detection methods were analyzed. All patients had axillary lymph node dissection (ALND)，and all none sentinel lymph nodes (NSLN) were examined by Hamp;E staining.ResultsThe SLNs were identified in 45 of 50 patients with a detection rate of 90%. Sixteen SLNs were found positive with routine histological exam, the positive detecting rate was 35.56%, while the other 29 negative SLNs were found 7 and 6 cases of micrometastasis using SS and IHC methods，therefore the positive detecting rate was increased by 15.55% and 13.33%, respectively.Conclusion SS and IHC methods could detect the micrometastasis in negative SLN with routinely histological exam, increasing the positive detecting rate and decreasing the false negative rate.