The invention discloses a non-solvent type water-soluble varnish and a preparation method thereof. The non-solvent type water-soluble varnish is a liquid formed by mixing non-solvent type water-soluble liquid resin with a curing agent. The preparation method comprises the following concrete steps of taking a water-soluble component, a hydrophobic component, an active organosilicon composition andthe like as main raw materials, synthesizing the non-solvent type water-soluble liquid resin through bulk copolycondensation reaction in the presence of catalyst, well mixing the curing agent with the resin and then obtaining the transparent non-solvent type water-soluble varnish. The preparation of the non-solvent type water-soluble varnish uses no organic solvent, and is simple in process and less equipment investment. The varnish is friendly to environment and can be widely used in the glass printing industry.