The invention discloses tungsten carbide thermal spraying powder for preparing a coating with the high bonding strength and the low porosity and a preparation method for the tungsten carbide thermal spraying powder. The tungsten carbide thermal spraying powder is composed of the following components of tungsten-carbide-based metal ceramic powder and metal elemental powder with the weight accounting for 0.3-2% of the total weight of the tungsten-carbide-based metal ceramic powder; and the metal elemental powder is attached to the surface of the tungsten-carbide-based metal ceramic powder. In the spraying process of the thermal spraying powder, the metal elemental powder and oxygen in the spraying atmosphere are subjected to an exothermic reaction under the environment of high temperature flame flow, the surface temperature of powder particles is raised through heat released by the reaction, the melting degree of the powder under different technological conditions is improved, the flattening effect of the spraying powder is better, thus the bonding strength between the flattened particles is improved, the porosity of the coating is reduced, and the problems that the coating is low inbonding strength and high in porosity in the spraying process of existing thermal spraying powder are well solved.