In this study, WC–17 mass%Co composite powder for HVOF (High Velocity Oxy-Fuel)-thermal spray was fabricated by the spray-drying method and the effect of heating temperature (850°C, 1000°C, 1150°C, 1300°C) on the microstructure, particle size distribution, flowability and phases was investigated. The as-spray dried powder had a spherical morphology and the particle size distribution, mean particle size, and flowability were 20.6–51.7 \\micron, 27.2 \\micron, and 3.8 g/s, respectively. The agglomerated powder became dense by heating. After heating at 1300°C, the particle size distribution and mean particle size were decreased to 6.9–37.9 \\micron and 17.8 \\micron, respectively. And the flowability was improved to 8.7 g/s. Accordingly, investigating the effect of heating temperature on particle size distribution, mean particle size, flowability, and microstructure of spray-dried WC–17 mass%Co powder, we found that the optimum heating temperature of spray-dried WC–17 mass%Co powder for HVOF-thermal spray powder ranged from 1150 to 1300°C. And during the heating, Co6W6C and Co3W3C phases were produced and the critical temperature transforming Co6W6C into Co3W3C phases was 1150°C.