Poly(vinyl alcohol) (PVA) fiber is widely used in many important high-tech areas due to its excellent comprehensive properties. However, due to the very difficult thermal processing of PVA, the PVA fiber is presently produced only by solution spinning. Melt spinning of PVA fibers is still a big challenge in the world. In our previous work, by adopting molecular complexation and plasticization, the stable thermal processing of PVA was realized. This paper reported a novel and environmental friendly technique to realize the melt spinning of PVA using water and an amido group containing compound (Ac) as modifier. The thermal processing mechanism, water states, water evaporation behavior, the rheology properties of modified PVA as well as the structure evolution of PVA fibers were systematically studied. The result showed that Ac could change the water state in PVA and retard the water evaporation effectively. The crystallinity of PVA decreased from 66.3% to 44.1%. Furthermore, the melting point of PVA decreased, which was far below its thermal decomposition temperature, providing the thermal processing window wider than 80℃. The shear viscosity of PVA melt met with the viscosity requirement of melt spinning. Accordingly, the melt spinning and high ratio drawing of PVA as-spun fibers were successfully realized, and PVA fibers with strength 1.9GPa and modulus 39.5GPa were obtained which was much higher than that of conventional wet-spun fibers. Also, the novel melt spinning offered a way to produce heavy denier PVA fibers, PVA functional fibers such as PVA/CNTs, PVA/Mg(OH)2 fibers, which can hardly be produced via solution spinning. By optimizing the melt spinning conditions and machinery, the first 50 t/a pilot melt-spinning line of PVA fibers in the world has been set up successfully, which is a big breakthrough in PVA fibers industry. We are grateful for the support of the National Natural Science Foundation of China (50673068, 50833003) and our industrial partner.