The invention provides a manufacturing method of a high-density tungsten carbide coating roll for a solvent-free compound machine. Aiming at meeting the requirements for high wear resistance, low porosity and low friction coefficient of a coating roll for the solvent-free compound machine, a method for adding 5%-50% by weight of spherical WC particles with particle size being 30-100 mu m to spraying powder of sintered or agglomerated Ni-based WC, Co-based WC or Co-Cr-based WC and the like is adopted, high-speed spherical WC particles rebound instead of depositing in a coating during spraying,under the beating action after rebounding, the coating is more dense and low in porosity, coating glue is not prone to sticking and is easy to clean during using, and transfer rate is high; meanwhile,binding force between particles in the coating is increased under the action of repeated beating of the spherical WC particles, the particles are not prone to stripping during high-speed wearing, wear resistance is improved, and service life of the roll is prolonged. Porosity of a metering roll, a glue transfer roll and the coating roll, manufactured with the method, of the solvent-free compoundmachine is lower than 0.4%, surface smoothness is high, Ra is smaller than 0.08 mu m, wear resistance and transfer rate are high, and the service life is prolonged by 5 times or more.