The invention discloses an aluminum foil for a lithium ion battery, a micro-porous aluminum foil, and a preparation method of the micro-porous aluminum foil. The aluminum foil comprises 0.14-0.16 wt%of Mg, 0.08 wt% or less of Si, 0.2 wt% or less of Fe, 0.03 wt% or less of Ga, 0.04 wt% or less of Cu, 0.04 wt% or less of Zn, 0.05 wt% or less of V, 0.03 wt% or less of Ti and 99.7 wt% of aluminum. The micro-porous aluminum foil is prepared through adopting a chemical corrosion technology; 300-6000 through holes and/or blind holes with the diameter being 6-12 [mu]m are distributed in per square centimeter of the micro-porous aluminum foil; and a defined component composition has a higher yield strength than existing series of aluminum alloys, and makes formed micro-pores have small and uniformapertures in the subsequent chemical corrosion process, and each of through holes and the blind holes is in circular arc transition with a material body, so the stress concentration is reduced, mechanical properties are enhanced, electrical properties are not weakened, and the micro-porous aluminum foil can be applied to the lithium battery.