Superheated spray is expected to improve spray atomization and evaporation processes by introducing fuel temperature as a new control parameter in spark-ignited direct-injection engines (Zeng et al., 2012a,b; Zeng et al., 2013). Spray structure transforms dramatically with increase in the fuel superheat degree. Since the structure transformation is most likely caused by the momentum and mass transportation phenomena between the liquid and gas phases involved in the spray, the velocity distributions of both fuel spray and surrounding air under various superheat degrees can be used to interpret the transformation mechanism. The spray velocity field was thoroughly investigated in both cross-sectional and axial directions by using a high-speed particle image velocimetry (PIV) system. The cross-sectional PIV result was summarized in Part I, which explains how the adjacent plumes interact with each other, resulting in various characteristic mass distribution patterns on the cross-sectional plane. This study unveils how individual plumes develop along its axial direction as a function of time and axial location during the transformation process. As the superheat degree increases, the spray structure transforms from individual, narrow jets to a single, solid-cone liquid spray, and finally to a corndog-shape structure with an inner vapor gas jet and outer liquid spray. The Ply results provide insight to the spray transformation processes under various superheated conditions. As the superheat degree increases, the vortex ring developed at the spray outer boundary near the spray tip region becomes stronger in terms of velocity magnitude and tighter in terms of vortex size. The vortex ring diameter keeps decreasing, which pushes the multiple plumes to the central axis. As a result, the plumes collapse into one single spray body with accelerated axial velocity and significantly reduced radial velocity.