Objective：To verify whether hot PBS washing after the enzymatic reaction between tyramine and horseradish peroxidase can improve the sensitivity and specificity of catalyzed signal amplification （CSA）. Methods： Using 7 different types of primary antibodies and 2 tumor microarray system, we carried out EnVision, LSAB, Standard CSA, and modified CSA staining and compared their sensitivities and specificities. Results： The modified CSA method was the most sensitive one among the 4 methods, followed by standard CSA, EnVision, and LsAB method. The sensitivity of modified CSA method was 2-3 times higher than that of standard CSA. The 4 methods had similar background staining and had exact localization of cells. Conclusion： The modified CSA is more stable and sensitive than traditional CSA staining method