The in-flight particle temperature and velocity are very important factors that determine the deposition characteristics and coating qualities in plasma spray. Therefore, predicting the in-flight particle temperature and velocity with spray conditions is benefit to control the prepared coating qualities. In the present study, a steady-state 3D model was used to calculate the gas flow field of a plasma jet. The plasma gas temperature and velocity profiles applied to the plasma jet as the boundary conditions were obtained with our previous studies of plasma arc behaviors inside plasma torch. After obtained the gas temperature and velocity of the plasma jet, the in-flight particle trajectories, temperature, and velocity were investigated with numerical calculation method. Also the inflight particle temperature and velocity were verified by experimental measurements.