Isobaric vapor-liquid equilibrium (VLE) data for the binary system ethyl propionate (2) + para-xylene (3) and ternary system ethanol (1) + ethyl propionate (2) + para-xylene (2) at atmospheric pressure (101.3 kPa) were obtained by a VLE modified othmer still. All the experimental data passed a point to point consistency test of Van Ness method, which verified the data reliability. The Wilson and UNIQUAC activity coefficient models were employed to correlate the binary VLE data to obtain binary interaction parameters. Based on binary interaction parameters, ternary VLE data of ethanol (1) + ethyl propionate (2) + para-xylene (3) were predicted by Wilson and UNIQUAC models, which proved that predicted values are consistent with the experimental data. Furthermore, azeotropic phenomenon between ethanol and ethyl propionate disappears when the mole ratio of para-xylene and binary system of ethanol and ethyl propionate is 1:1. Therefore, this paper convinced that para-xylene is a proper extractive additive that could be used in extractive distillation to separate the binary azeotropic system of ethanol and ethyl propionate. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.