The invention discloses a cooling water composite corrosion and scale inhibitor and preparation and application thereof. The cooling water composite corrosion and scale inhibitor comprises the following compositions by weight percentage: 5 to 40 percent of phosphonyl acetic acid, 10 to 40 percent of amino ether phosphonic acid, 1 to 10 percent of poly(acrylic acid), 0.1 to 1 percent of zinc salt,and the balance being water. The cooling water composite corrosion and scale inhibitor is suitable for various cooling water systems in the automobile production industry and particularly has good scale inhibiting effect on cooling water systems with high weight concentration, high alkalinity, high hardness and high pH value.