The centrifugal atomization process of liquid by a spinning disk has been investigated by visualized experiments. First, the nondimensional critical equations are derived theoretically and obtained from the experimental data. Accordingly, a transition map is proposed to analyze the effects of operating conditions Piquid flow rate Q angular speed w, and disk diameter D) and liquid properties (fluid density p, fluid viscosity it, and surface tension a) on the transition characteristics of spinning -disk atomization. The results indicated that the transitions of direct drop ligament and ligament sheet modes are promoted with an increase of Q, omega, rho, and mu. For the-transition of direct drop ligament mode, the critical volume flow rate will not always rise with increasing D. By contrast, the reduction in the critical volume flow rate can be attributed to the incomplete wetting of the disk surface. In full ligament breakup stage, the increased Q creates a longer ligament length and a wider ligament diameter, while the number of ligamentS remains constant.