Acetic ether was used as solvent for extraction of resorcinol under the environment of acid brine. Liquid-liquid equilibrium (LLE) data of acetic ether-resorcinol-acid brine quasi ternary system were determined at atmospheric pressure (101.33 kPa) and 313 K with the equilibrium method. The experimental data showed that the mutual solubility of acetic ether and water was increased with increasing resorcinol which reduced the extraction effect of the acetic ether on resorcinol

while the solubility of acetic ether in water was reduced in the existence of ammonium sulphate which was good for the extraction process. The experimental data were correlated with NRTL model and parameters were obtained. The calculation results agreed well with the experimental data

indicating that the models used were suitable for the system. The model also provided data for the design of extraction process of m-phenylenediamine hydrolysis for joint production of resorcinol with m-aminophenol.