The invention discloses a micro-emulsion cutting fluid for aluminum alloy and a preparation method of the micro-emulsion cutting fluid. The micro-emulsion cutting fluid comprises the following raw materials in parts by weight: 12-16 parts of paraffin-based oil, 3-5 parts of star anise oil, 4-7 parts of eucalyptus oil, 5-7 parts of sorbitan fatty acid, 3-4 parts of triethanolamine oleate, 3-4 parts of petroleum sodium sulfonate, 7-8 parts of sorbitan monooleate, 3-4 parts of monoethanolamine, 6-7 parts of zinc sulfate, 4-7 parts of sodium oleate, 6-8 parts of dimethicone, 2-4 parts of sodium molybdate, 4-7 parts of octylphenol polyoxyethylene ether, 4-7 parts of chlorinated paraffin, 4-5 parts of ricinoleic acid, 0.5-1.5 parts of dodecanol, 1.2-1.5 parts of imidazolidinyl urea, 10-15 parts of additives and 15-25 parts of deionized water. The micro-emulsion cutting fluid for aluminum alloy also has the outstanding performances on the aspects of corrosion inhibition property, corrosion resistance, lubrication, rust resistance, defoaming property, service life and the like.