MetQ gene of Streptococcus suis serotype 2 deletion strain has attenuated antiphagocytosis. However,the mechanism of antiphagocytosis and pathogenesis of MetQ in SS2 has remained unclear. In this study, stable isotope labeling by amino acids in cell culture (SILAC) based liquid chromatography-mass spectrometry (LC-MS) and subsequent bioinformatics analysis was used to determine differentially expressed proteins of RAW264.7 cells infected with △MetQ and ZY05719, aimed at elucidating the mechanism of antiphagocytosis and innate immunity of macrophages infected by Streptococcus suis.