Molybdenum-ruthenium powder is widely used as high-temperature brazing filler material. In this study, micro-spherical Mo-Ru particles were synthesized by spray drying combined with calcination technique from commercial (NH4)(6)Mo7O24 and (NH4)(2)RuCl6 powders. Micro-spherical (NH4)(6)Mo7O24 and (NH4)(2)RuCl6 mixture particles were achieved by spray drying treatment. The influences of calcination temperature on crystallization, morphology and size of as-synthesized Mo-Ru particles were investigated. The composition of as-synthesized Mo-Ru particles were Mo0.3124Ru0.6876 alloy and elemental Mo. Porous tungsten cylinders and molybdenum cylinders were welded together using the assynthesized Mo-Ru powder. There was no any cracks around the welding region. The average tensile strength of welding samples was 76.65 +/- 1.15 MPa. The results show that this is an excellent method to prepare molybdenum-ruthenium powder by spray drying combined with calcination. It should be noted that the powder technology in this study can be applied to synthesize other alloy powders (binary, ternary and more) with high-performance requirements. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.