The invention relates to a composite microbial agent for treating domestic garbage and a method for treating the domestic garbage by using the composite microbial agent. The composite microbial agent for treating the domestic garbage is prepared from the following components: brevendimonas diminuta, pseudomonas stutzeri, pseudomonas maltophilia, pseudomonas fluorescens, pseudomonas putida, candida utilis, candida lipolytica, schizosaccharomyces pombe, schizosaccharomyces octosporus, bacillus megatherium, bacillus subtilis, bacillus cereus, alcaligenes faecalis, clostridium beijerinckii, achromobacter denitrificans, nocardia coralline, and the like, wherein the parts by weight of the brevendimonas diminuta are 1-5, the parts by weight of the pseudomonas stutzeri are 1-5, the parts by weight of the pseudomonas maltophilia are 1-5, the parts by weight of the pseudomonas fluorescens are 1-5, the parts by weight of the pseudomonas putida are 1-5, the parts by weight of the candida utilis are 1-5, and the parts by weight of the candida lipolytica are 1-5.