Continuous production system of poly(trimethylene terephthalate)

The invention relates to a continuous production system of poly(trimethylene terephthalate) (PTT). The system comprises an esterification subsystem, a polycondensation subsystem and a granulating crystallization drying subsystem that are connected in order. A gas outlet of the esterification subsystem is connected to an inlet of a process tower for preliminary distillation of discharged gas from esterification. A liquid outlet of the process tower is connected to an inlet for a PDO mixture to be refined in a refining device. A discharged gas outlet of a polycondensation reactor in the polycondensation subsystem is in connection with an corresponding inlet for a medium to be leached in a spraying device. A liquid outlet for refined PDO in the refining device is in connection with a PDO rawmaterial inlet of the esterification subsystem and/or a spraying medium inlet of the spraying device. Employment of the system provided in the invention can continuously and stably realize the whole process from PTT material production to PTT granulation, crystallization, drying and packaging, and also can realize the utmost recycling of 1, 3-propanediol within the system, thus substantially reducing production cost.