The invention discloses a method for catalyzing lactide polymerization by utilizing a chiral asymmetric aluminum complex containing a salicylaldehyde group. The method comprises the following steps: mixing a catalyst, an organic solvent, a benzyl alcohol co-catalyst and lactide; carrying out ring-opening polymerization reaction under water-free and oxygen-free, and inert gas protection conditions;after reacting, treating a reactant to obtain polylactide, wherein the catalyst is the chiral asymmetric aluminum complex containing the salicylaldehyde group. According to the method disclosed by the invention, the own researched chiral asymmetric aluminum complex containing the salicylaldehyde group is used as a catalyst for carrying out the lactide ring-opening polymerization reaction; the catalyst has the advantages of simple preparation method, low cost, diversified structure changes, high catalytic activity, high stereoselectivity and rapid reaction speed; a polymer obtained by reactionis a benzyloxy-terminated complex, has the advantages of narrow molecular weight distribution, controllable molecular weight and high yield and can meet the requirements of the market.