The invention relates to an anti-yellowing cationic water-based polyurethane leather finishing agent, and belongs to the technical field of textile chemicals. The anti-yellowing cationic water-based polyurethane leather finishing agent is prepared by using polyalcohol, aliphatic diisocyanate, diethanol amine and a cross-linking agent as raw materials to synthesize cationic water-based polyurethane, and adding an antioxidant and an uvioresistant absorbent for modifying the cationic water-based polyurethane. The prepared cationic water-based polyurethane finishing agent has the advantages of high stability, yellowing resistance and the like.