Polyoxymethylene dimethyl ethers (PODEn) are promising diesel additives which can be synthesized from formaldehyde and methanol. In this work, the ternary liquid-liquid equilibria (LLE) were analytically determined at 293.15 K and 313.15 K for the following systems: PODE1+para-xylene(PX)+water, PODE2+PX+water, PODE3+PX+water, PODE4+PX+water, respectively. The isothermal experimental results have shown a good linear fit in Hand plots and the Othmer-Tobias. The design of the solvent extraction equipment for extracting PODEn from aqueous solution requires an appropriate model for the liquid-liquid phase equilibrium. The wellknown NRTL and UNIQUAC thermodynamic models were applied to correlate the experimental data, and the results indicate that the UNIQUAC model gives a better agreement.