The isobaric vapor-liquid equilibrium (VLE) data of 1-methoxy-2-propanol (PM) + 1,2-propanediol (PG) and 2-methoxy-1-propanol (MP) + 1,2-propanediol (PG) was measured in this work by a modified Rose-Williams still under pressures of 101.3 kPa and 50.0 kPa. The Wisniak test and the Van Ness test were applied to confirm the thermodynamic consistency of the VLE data. The experimental isobaric VLE data were correlated by the nonrandom two-liquid and universal quasichemical models. The experiment results showed that these two models perfectly correlate the measured VLE data.