Abstract: Molecular connectivity indices (MCIs) of all 209 possible molecular structure patterns of polychlorinated diphenyl ethers (PCDEs) were calculated.Combined these MCIs with three observed partition properties of 106 PCDEs, i.e. vapor pressure ( P^O_L),aqueous solubility ( S_w) and n-octanool/water (K_ow),a series of quantitative structure property relationship (QSPR) equations were built up.The best three equations were determined with significant correlation.With the equations the three properties of other 103 patterns of PCDEs were predicted and then other three partition properties for all PCDEs,i.e.Henry’s constants,gas/water partition coefficients (K_gw) and gas/n-octanol partition coefficients (K_go),were calculated out.