Fabrication of feedstock powders is a critical technology that directly influences the microstructure and performance of plasma-sprayed coatings. Conventional boron thermal reduction methods for synthesizing high-entropy boride powders encounter several limitations such as prolonged processing time, impurity contamination, and inability to obtain spray-ready powders. In this work, an inductive plasma spheroidization (IPS) process was employed to fabricate (Zr_1/4Hf_1/4Ta_1/4Ti_1/4)B₂ high-entropy powders for plasma spraying in contrast to the other two traditional powder preparation routes. The morphology, internal structure, particle size distribution, density, and other fundamental properties of powders were systematically characterized. The effects of different powder fabricating processes on the microstructure and fundamental properties of high-entropy boride powders were systematically investigated, thereby validating the broad applicability of this methodology for synthesizing high-entropy boride powders. The results demonstrate that using commercial micron-sized boride powders as precursors, a hybrid process combining mixing, spray drying, sintering with IPS facilitates the fabrication of high-entropy powders with homogeneous elemental distribution. The resulting powders exhibit spherical morphology, smooth surfaces, high internal density, and high apparent/tap density. Further experiments on synthesizing different high-entropy borides with varied compositions confirm the extensive applicability of this method. The formation mechanism of high-entropy solid solutions is elucidated through first-principles calculations combined with the unique characteristics of IPS process. This work proposes a promising method for fabricating high-entropy ceramic powders suitable for plasma-spray coatings.