Simulations of a continuous recycle process were carried out for the direct esterification between terephthalic acid and ethylene glycol in the production of poly(ethylene terephthalate). The influence of reaction pressure, recycle ratio and residence time on the oligomer characteristics was examined and the following results were obtained: (1) The main reactions go on further under higher reaction pressure but the side reactions on diethylene glycol (DEG) proceed to a greater extent than the main reactions. (2) The higher residence time ratio of the first reactor to the total promotes esterification remarkably as the pressure becomes high. (3) As the recycle ratio becomes high, the polymerization degree becomes high, but, at higher degrees of polymerization, the tendency is reversed. (4) The oligomer characteristics are almost the same at the same esterification degree independently of the reaction conditions.