The invention discloses a hot-pressed veneer adhesive and a preparation method thereof. The hot-pressed veneer adhesive mainly comprises the following components: deionized water, polyvinyl alcohol, an emulsifier, an initiator, methacrylic acid, N-methylol acrylamide, vinyl acetate, a plasticizer, a buffering agent, cassava starch, borax, a dispersing agent, aqueous rosin, a defoaming agent and a corrosion inhibitor. When the hot-pressed veneer adhesive is prepared, the preparation method comprises the following steps of: firstly synthesizing a self-crosslinked polyvinyl acetate copolymerization modified emulsion, then adding 20-35% of raw cassava starch, a crosslinking agent, waterborne tackifying resin and other auxiliaries for mixing and finally preparing the hot-pressed veneer adhesive with excellent performances. Compared with a traditional urea resin veneer adhesive, the adhesive prepared by the invention has the advantages of convenience in use, low curing temperature, short curing time and no harm to an environment and a human body.