In this study, high-speed melt spinning for three kinds of high molecular weight poly(ethylene terephthalate) (PET) was conducted to investigate effect of molecular weight on the structure and properties of obtained as-spun fibers. Intrinsic viscosities of used high molecular weight PET materials were 0.8dl/g, 1.21dl/g and 1.38dl/g, respectively, and as-spun fibers of each PET material were prepared in the 1~6km/min range on the spinning velocity. Structure and properties of obtained as-spun fibers were analyzed by measurements of differential scanning calorimeter(DSC), birefringence, wide-angle x-ray diffraction(WAXD), and tensile property, etc. Typical structural evolution by strain-induced crystallization started to show from high speed of 4~5km/min and the degree of crystallinity and crystal orientation of as-spun fibers obtained at 6km/min increased in proportion with molecular weight. On the other hands, effect of molecular weight on the mechanical properties and birefringence of as-spun fibers was relatively small and limited.