The invention discloses workshop primer and a preparation method thereof and belongs to the technical field of preparation of paint. The preparation method comprises the following steps: preparing silane hydrolysate by utilizing ethanol, vinyltriethoxysilane and the like; filling zinc powder into a vacuum furnace and evaporating to prepare zinc steam; condensing the zinc steam into powder; after grinding and sieving, immersing and laminating by utilizing a lanthanum salt treatment solution prepared by mixing hydrogen peroxide and a lanthanum nitrate solution; then immersing with the silane hydrolysate and carrying out sealing treatment on a lanthanum film to prepare composite film sheet-shaped nano zinc powder; carrying out dispersion treatment on organic bentonite, quartz powder, the composite film sheet-shaped nano zinc powder and the like to obtain a component A; then mixing sodium methyl silicate, hydrochloric acid and the like to prepare a component B; stirring and mixing the component B and the component A to obtain the workshop primer. The workshop primer prepared by the preparation method has excellent thermal stability, weather resistance and film-forming stability; an anti-rust period of the primer is effectively prolonged; the workshop primer has a better protection effect on a steel component and has a wide application prospect.