The invention relates to a preparation method and application of environment-friendly urea resin for laminating plywoods from high water-content veneers. The method for synthesizing the resin is simple, and low in cost; the laminated plywoods can meet the national E1 grade and even E0 grade environmental protection requirements; and the problems of low prepressing performance and water resistancewhen the high water-content veneers are laminated into the plywoods are mainly solved. In the synthesis of the urea resin, an acid-base-acid-base process is adopted, formaldehyde and polyvinyl alcohol are added at one time, urea is added by three batches, melamine is added by two times, and after ammonia water is added, the ammonia water, the urea, the formaldehyde and urea-form condensate are reacted to generate a series of triazine ring compounds, and the microstructure of the resin is improved. When the resin is cured, the crosslinking density is improved, wet shear strength of the plywoods is obviously improved and the formaldehyde emission is obviously reduced.