Among the many uses of polyester PET (polyethylene terephthalate), polyester industrial silk belongs to the variety with high technical threshold. Polyester industrial silk has high strength, fatigue resistance and aging resistance, used in geotechnical materials, tire cord, automotive safety belt and other fields. The higher the mechanical properties of polyester PET products are, the greater the relative molecular mass is required, and the higher the corresponding melt dynamic viscosity is. Conventional melting and polycondensation can only improve the PET characteristic viscosity to about 0.65 dl / g, which can only be used for spinning civil polyester fiber, while the polyester raw materials required for the production of polyester industrial silk must pass the "post-reinforcement phase condensation" process to meet the viscosity requirements. In recent decades, the global polyester industrial silk production has adopted the high energy consumption "three-section method" production process (slice spinning process), which first uses fusion, then solid phase cohesion, and then screw melt extrusion spinning. The whole process has long time, complicated process, low efficiency and non-continuous process. Well-known foreign companies such as DuPont of the United States and Hitachi of Japan have been committed to the research of melt direct spinning polyester industrial silk technology, but they have not achieved large-scale industrialization.