The reactor consists of a reaction vessel, a stirrer and transmission system, cooling equipment, safety devices, and a heating furnace. The esterification/polycondensation reactor is a device that completes esterification and polycondensation simultaneously. When the esterification/polycondensation reactor is used for esterification, water and low-molecular substances produced during the esterification reaction are separated out through a rectification column, packed tower, and condenser. When the reactor is used for polycondensation, the esterification valve is closed, the polycondensation valve is opened, and the temperature is adjusted to a higher level. The interaction of many similar or different low-molecular substances is facilitated by the stirring system, generating high-molecular substances. At the same time, the precipitated low-molecular substances are collected and separated by the condenser receiver. The esterification/polycondensation reactor is widely used in organic synthesis, chemical fiber, and other fields.