The interaction of Deltamethrin (DM) with human serum albumin (HSA) under the condition of simulating human blood pH environment (pH = 7.4) was investigated by fluorescence, UV-Vis absorbance and circular dichroism (CD) spectroscopy. It was shown that DM was a static quencher of HSA. The binding constants (Ka) are 3.598 x 10(4) L mol(-1) (25 degrees C); the thermodynamic parameters (Delta H = -3.269 x 10(4) kJ mol(-1), Delta S = -22.81 kJ mol(-1) k(-1), Delta G = 25889.8 kJ mol(-1)) obtained with the thermodynamic equation. The hydrogen bond and Vander Waals were the main driving force. The effect of DM on the conformation of HSA was observed by three-dimensional (3D) fluorescence and circular dichroism spectra, indicating that the interaction between DM and HSA was achieved through the binding of DM with the tryptophan and tyrosine residues of HSA. The study on the interaction of DM and Bovine Serum Albumin (BSA) was researched and compared. Difference exists in the interactions of with each of the serum albumins. We will verify and supplement that DM residue in animals and human metabolism, toxicology and other mechanisms are different. (C) 2016 Elsevier B.V. All rights reserved.