The invention discloses a coating fertilizer special for soybean and a preparation method for the coating fertilizer. The coating fertilizer consists of a fertilizer core and a coating layer, wherein the coating layer comprises a mixture of phosphate tailings and a solution obtained by performing condensation reaction on polyvinyl alcohol and one of formaldehyde, acetaldehyde, propionaldehyde andbutyraldehyde in a weight ratio of 15:(2-10); the phosphate tailings account for 5 to 25 percent of the total weight of the mixture; and the weight of the dried coating layer is 8 to 30 percent of the total weight of the coating fertilizer. The coating fertilizer has high sustained release performance, can fully meet the requirement of the soybean on nutrients, and improves the yield and quality of the soybean.