TMolecular electronegativity-distance vector (MEDV) was used to describe the molecular structures of 165 nonionic organic compounds in this paper.A quantitative linear relationship between 32 MEDV descriptors and bioconcentration factor (BCF) of 122 NOC was set up using a multiple linear regression (MLR).The satisfactory model of 4 parameters (such as M15,M17,M36,M91),which the calibrated correlation coefficient was 0.960 and the validated correlation coefficient (q2) was 0.915,were built by stepwise multiple regression and the Jackknifed method (the leave-one-out,LOO).The 4-variable model has shed light on some main structural factors influencing the BCF of NOC,which shows the good estimation ability and robustness.A prediction power for the external sample of 11 NOC was validated by the model built from the training set with 111 NOC.