The invention provides a catalyst ligand, a catalyst, and preparation methods and application thereof. The catalyst prepared from the ligand provided by the invention is applicable to polymerization of olefins, and is well active to homopolymerization and copolymerization of the olefins; the molecular weight of an obtained polymer is high, and the proportion of polar monomers doped during the copolymerization is higher; in addition, the catalyst provided by the invention can also catalyze the conducting of a polymerization reaction at the room temperature of 20 DEG C.