The invention relates to a palladium-containing catalyst and a preparation method thereof, a composition prepared from the palladium-containing catalyst, and application of the composition. The structural formula of the palladium-containing catalyst is described in the description. The preparation method of the palladium-containing catalyst comprises the following steps: firstly, dissolving 2-hydroxy-1,4-naphthoquinone and substituted aniline into an organic solvent for carrying out a reaction so as to obtain an aniline naphthoquinone ligand; dissolving the aniline naphthoquinone ligand into an organic solvent, and adding a hydrogen extraction reagent for carrying out a reaction so as to obtain a ligand salt compound; adding a palladium precursor into the ligand salt compound for carryingout a reaction so as to obtain an intermediate metal complex; finally, adding a pyridine reagent into the intermediate metal complex for carrying out a reaction to obtain the catalyst. The compositioncan be prepared from the palladium-containing catalyst and a catalyst promoter. The palladium-containing catalyst uses palladium as a metal center, is higher in activity of catalyzing homopolymerization of ethylene and copolymerization of olefin and a polar monomer, also can reach a certain activity without needing a catalyst promoter, and is good in economical efficiency and high in polarity/functional monomer insertion rate. The composition prepared from the palladium-containing catalyst has higher catalytic activity when a very small amount of the catalyst promoter is used.