The invention discloses a composite microbial deodorizer, comprising, by weight, 25-35 parts of a composite bacterial liquid, 20-30 parts of molasses, 0.1-0.5 part of composite vitamin liquid, 0.3-1 part of trace elements, and 40-50 parts of water. The composite bacterial liquid comprises, by weight, 12-15 parts of Rhodopseudomonas palustris, 10-13 parts of Bacillus subtilis, 10-13 parts of Bacillus licheniformis, 7-10 parts of Lactobacillus, 10-14 parts of composite photosynthetic bacteria, 6-8 parts of Saccharomyces cerevisiae, 5-8 parts of nitrobacteria, 6-10 parts of nitrite bacteria, and5-10 parts of thiobacillus; a culture medium comprises, by weight, 0.2-0.4 part of maltose, 0.8-1.2 parts of beef extract, 0.08-0.12 part of zinc sulfate, and 93-96 parts of water. The total effectivebacterial count is greater than 0.35 billion per milliliter, the Saccharomyces count is greater than 10 million per milliliter, the bacillus count is greater than 60 million per milliliter, and the Monoucleosis account is greater than 30 million per milliliter. The composite microbial deodorizer has high deodorizing efficiency, little negative effect and high economic benefit.