Human stool samples were collected, microbial cells were harvested and subjected to protein extraction using different protocols for metaproteomics analyses. The protein extraction methods differ from the usage of different lysis buffer (SDS, urea and commercially available B-Per reagent), bead beating, ultrasonication and heating. The impacts of different protein extraction methods on metaproteomics results were evaluated with multiple criteria including protein yields, peptide identifications, taxonomic compositions and functional compositions.