Organophosphate flame retardants (OPFRs) are ubiquitous in the environment. To better understand and predict their environmental transport and fate, well-defined physicochemical properties are required. Vapor pressures (P) of 14 OPFRs were estimated as a function of temperature (T) by gas chromatography (GC), while 1,1,1-trichioro-2,2-bis (4-chlorophenyl) ethane (p,p'-DDT) was acted as a reference substance. Their log PGC values and internal energies of phase transfer (△ vapH) ranged from -6.17 to -1.25 and 74.1 kJ/mol to 122 kJ/mol, respectively. Substitution pattern and molar volume (VM) were found to be capable of influencing log PGC values of the OPFRs. The halogenated alkyl-OPFRs had lower log PGC values than aryl-or alkyl-OPFRs. The bigger the molar volume was, the smaller the log PGC value was. In addition, a quantitative structure-property relationship (QSPR) model of log PGC versus different relative retention times (RRTs) was developed with a high cross-validated value (Q2cum) of 0.946, indicating a good predictive ability and stability. Therefore, the log PGC values of the OPFRs without standard substance can be predicted by using their RRTs on different GC columns.