Esterification polycondensation reactor is a kind of reaction device which can accomplish both esterification and condensation. When esterification polycondensation reactor is used as esterification reaction, water and low molecular weight substances produced by esterification reaction are separated by distillation column, packing tower and condenser. When esterification polycondensation reactor is used as condensation reaction, the esterification reaction valve is closed and the polycondensation valve is opened, and the temperature is adjusted to higher temperature. Many identical or different low molecular weight substances are interacted by stirring system to form high molecular weight substances. At the same time, the precipitated small molecules are separated and collected through the condenser receiving tank. Esterification polycondensation reactor is widely used in organic synthesis, chemical fibers and other fields.