The starting powder quality significantly influences the process window optimization and properties of parts fabricated by additive manufacturing. In this study, we investigated the influence of plasma rotating electrode process (PREP) parameters on the particle size distribution and microstructure of Ti-6Al-4 V alloy powder. The martensite size in the powder decreased with increasing rotating electrode speed owing to the higher cooling rate. Numerical simulations using computational thermal fluid dynamics were found to be feasible for quantitative evaluation of the temperature variation, cooling rate, and powder size during PREP, which provide a new strategy to study the mechanism of powder formation. In addition, a statistical model combining principal component analysis and the Monte Carlo methods was proposed to evaluate the relationships between PREP parameters and average powder diameter based on the limited collected experimental data. The proposed statistical model can also be applied in research fields where multivariable problems exist. (C) 2020 Elsevier B.V. All rights reserved.