Abstract: The Invention provides golf balls formed from the cover compositions comprising a modified ionomer resin which is obtained by adding and reacting with a polyester oligomer in a zirconium complex and zirconia filled state to a typical ionomer resin, said ionomer resin being prepared by neutralizing a part of the unsaturated carboxylic acid with metals including zirconium, being addition polymerization with another ester by a radical reaction. A golf ball having a cover prepared from the compositions, the carry distance has increased in hitting the golf ball with a driver and excellency in back-spin property in hitting with a short iron, and the golf ball has a soft feeling with a durability, so that being got rid of a defect of a golf ball which has a cover composition comprising a conventional soft type ionomer resin, satisfying the golfers.