During the process of wheat Qu-making,a series of metabolic reactions originated from microorganisms inoculated naturally occur to provide various enzymes and flavour compounds precursors for fermentation of Shaoxing Rice Wine.According to metaproteomics,two-dimensional electrophoresis(2-DE) and tandem mass spectrometry(MS/MS) methods were used to analyze the extracts of "wheat Qu" during the six making-stages(including starting period,early-fermentation period,warming period,high-temperature period,cooling period and mature period).By comparative analysis of the 2-DE maps by using the PDQuest software,12 spots with dramatic variations of expression level were found and subsequently identified by MALDI-TOF/TOF MS.Among the 7 protein spots which were identified successfully,there were 4 spots from microbes,including the coagulation factor with 5/8 type domain protein(Amycolatopsis mediterranei U32),the malate dehydrogenase(Micromons sp.RCC299),carboxypeptidase T precursor and glucose-6-phosphate isomerase(Saccharopolyspora erythraea NRRL 2338).The other 3 protein spots were the hypothetical protein(Ectocarpus siliculosus),xylanase inhibitor protein and class II chitinase(Triticum aestivum).