The invention relates to a preparation method of a benzene-free net-flavour scratch-resistant polyurethane (PU) gloss varnish comprising an A component and a B component, and the weight ratio of A component to B component is 1:0.5; the A component resin paint comprises benzene-free net-flavour alkyd resin containing no vegetable oil (fatty acid), acrylic resin, aldehyde and ketone resin, a chelating leveling agent, a defoaming agent and a solvent; the component B comprises a curing agent and a solvent. The prepared benzene-free net-flavour scratch-resistant polyurethane (PU) gloss varnish does not contain aromatic hydrocarbons, ketones and heavy metals, 48 hours after coating for film formation, solvent smell is not left; and the benzene-free net-flavour scratch-resistant polyurethane (PU) gloss varnish has a high-gloss paint film, looks and feels like crystals and jades, is glittering and translucent and rich in paint film texture, has a smooth and bright mirror-like decorative effect, can create a fresh, simple, elegant, brief and quiet space, brings people unique relaxed and happy experience to adapt to modern people's aesthetic view, is very popular with the favor of the market and customers, and can be widely used in protection and decoration of the surface of wood, metal, plastic and other products.