Abstract: A PET industrial yarn melt direct spinning manufacturing method and a device thereof are disclosed. The device includes a polymerizer preparing base polyester melt, liquid tackifying reactors, and multi-head spinning units. The liquid tackifying reactors are connected with the polymerizer through split-flow pipelines respectively and after tackified by the tackifying reactors, the base polyester melt has its intrinsic viscosity reaching 0.90-1.10 dL/g. Each of the liquid tackifying reactors is connected with spinning units, and the spinning units are connected to the liquid tackifying reactors through melt pipelines. Each of the spinning units is provided with spinning boxes. The device solves the transportation problem of melt with high viscosity, combines both scale efficiency of the condensation production and market demand of multiple PET industrial yarns, and has the characteristic of integrating flexible production and intensive production.