Provided are a novel polyketone polymerization catalyst and a method of preparing a ligand, which can reduce production costs and can enable commercial mass synthesis by using ((2,2-dimethyl-1,3-dioxane-5,5-diyl)bis(methylene))bis(bis(2-methoxyphenyl)phosphine) as a ligand constituting the polykeytone polymerization catalyst, the ligand having a simple structure and a small molecular weight while having high activity.