Spherical powder has been widely used in injection molding, spraying, additive manufacturing and other fields due to its good flowability, high apparent density and tap density. The irregular tungsten powder was selected as raw materials to preparing spherical tungsten powder by radio frequency plasma system, and the effect of spherical tungsten powder was evaluated by laying powder and forming result. In the process of preparing spherical tungsten powder, the effects of process parameters (feeding rate, feeding position) and raw tungsten powder on spheroidization results were studied. In the aspect of laying powder experiment, the effect of powder characteristics and layer thickness on laying powder effect were studied. The morphologies, particle size distribution, flowability, apparent density and tap density of the tungsten powder before and after spheroidization were characterized by scanning electron microscopy (SEM), laser micron sizer, BT-100 multifuctional powder physical property tester. The results showed that tungsten powder was regularly spherical and had smooth surface after spheroidization, and the spheroidization rate can reach 100%. And the flowability, apparent density and tap density were improved obviously. The better the flowability of spherical tungsten powder with high spheroidizing rate, the better the effect of laying powder. With the increase of layer thickness, the effect of laying powder was improved gradually. And thin-walled parts were prepared by spherical tungsten powder of suitable particle size had low surface roughness and high dimensional accuracy.