The invention relates to a composite conditioner for a kitchen waste compost, which is composed of the following components in parts by mass: 10-20 parts of crop straw, 1-2 parts of fly ash and 2-3 parts of potassium carbonate. The invention also relates to a deodorizing method of a kitchen waste compost, which comprises the following steps: thoroughly mixing the composite conditioner and kitchen waste, and composting the uniform mixture in a composting device, wherein the mass ratio of the crop straw in the composite conditioner to the kitchen waste is (10-20):(90-80). The method is simple to operate and easy to implement. By adjusting the composting material structure and adding some chemical materials, the method controls the indirect odor emission source (leachate) in the form of liquid in the composting process, implements great emission reduction of the direct odor emission source, and improves the peripheral environmental quality of the existing composting plant. Meanwhile, the method promotes the recovery of crop straws and other agricultural wastes.