Density functional theory(DFT)-B3LYP level with the 6-311G**(d,p) basis set was used to calculate a set of molecular quantum chemical descriptors of 12 chloroanilines. Quantitative structure-activity relationship(QSAR) models of the bioconcentration factors(BCF) of the anilines in fish were established using some of the following calculated descriptors: EHOMO, ENHOMO, ELUMO, ENLUMO, ΔE1(= ELUMO- EHOMO), ΔE2(= ENLUMO- ENHOMO), dipole moment(μ), molecular volume(V), vibrational energy of 0 K(Ev), thermodynamic energy(E), heat capacity(Cv), entropy(Sm) and the charge of benzene ring(Qph). Using the variable selection and leaps-and-bounds regression, the quantum chemical descriptors derived directly from the molecular structures were employed to develop a linear QSAR model between the bioconcentration factors(BCF) and two descriptors(Sm, ENHOMO) of 12 chloroanilines. Statistically, the most significant one is a two-parameter linear equation with the correlation coefficient(R2) of 0.981 and cross-validated correlation coefficient(Rcv2) of 0.967. The established QSAR model has good stability and predictability based on the results from Rcv2 of leave-one-out cross-validation, AIC, FIT and tα/2. The quantum chemical analyses were performed from two aspects of frontier molecular orbital and entropy. The results show that two structural describers are crucial to the bioconcentration activity of chloroanilines. Density functional theory (DFT) -B3LYP level with the 6-311G ** (d, p) basis set was used to calculate a set of molecular quantum chemical descriptors of 12 chloroanilines. Quantitative structure-activity relationship (QSAR) models of the bioconcentration (BCF) of the anilines in fish were established using some of the following calculated descriptors: EHOMO, ENHOMO, ELUMO, ENLUMO, ΔE1 (= ELUMO- EHOMO), ΔE2 (= ENLUMO- ENHOMO) volume (V), vibrational energy of 0 K (Ev), thermodynamic energy (E), heat capacity (Cv), entropy (Sm) and the charge of benzene ring (Qph). Using the variable selection and leaps-and-bounds regression, the quantum chemical descriptors derived directly from the molecular structures were employed to develop a linear QSAR model between the bioconcentration factors (BCF) and two descriptors (Sm, ENHOMO) of 12 chloroanilines. Statistically, the most significant one is a two-parameter linear equation with the correlation coefficient (R2) of 0.981 The established QSAR model has good stability and predictability based on the results from Rcv2 of leave-one-out cross-validation, AIC, FIT and tα / 2. The quantum chemical analyzes were performed from two aspects of frontier molecular orbital and entropy. The results show that two structural describers are crucial to the bioconcentration activity of chloroanilines.