The invention provides a synthetic method and application of 1:2 type enol quinoline aluminium metal complexes. The method is characterized by using an enol quinoline coordinated ligand as a transfer reagent to react with alkylating reagents of metals to synthesize a series of metal complexes. Such kind of enol quinoline metal complexes can be used for catalyzing ring opening polymerization of aliphatic lactones. The method for synthesizing the complexes is simple, is lower in condition requirements and is higher in yield. The synthesized complexes have good catalytic activities and higher selectivity in ring opening polymerization of lactones. Such kind of complexes can be used for catalytically synthesizing biodegradable polyester materials.