The modifier of quantum dots plays an important role in synthesis and nature of quantum dots, however the effect on the interaction between quantum dots and protein is not very clear until up to now. In the present paper, the interactions of CdTe quantum dots with bovine serum album (BSA) were studied by spectroscopy methods including ultraviolet-visible absorption spectrometry (UV-Vis), fluorescence spectrometry (FL) and infrared spectrometry (IR). The CdTe quantum dots were modified by three different thiol-complex including thioglycolic acid, L-cysteine and glutathione, i.e. thioglycolic acid capped CdTe quantum dots (CdTeT), L-cysteine capped CdTe quantum dots (CdTeL) and glutathione capped CdTe quantum dots (CdTeG) respectively. The quenching constant KSV and corresponding thermodynamic parameters, such as enthalpy change (ΔHθ), entropy change (ΔSθ), Gibbs free energy change (ΔGθ), were calculated according to Stern-Volmer equations. The results showed that CdTeT, CdTeL and CdTeG all have a strong ability of quenching the fluorescence of bovine serum albumin, and the interactions of the three types of thiol-capped CdTe quantum dots with BSA were static quenching process. The quenching constant of KSV (TGA) is similar to KSV (GSH), which is much less than KSV (L-Cys). The binding forces of CdTeT and CdTeL with the BSA were the main contributions from hydrophobic force according to the thermodynamic parameters (ΔHθ>0, ΔSθ>0 and ΔGθ<0), while the binding forces of CdTeG with BSA were composed of both hydrogen bonding force and hydrophobic force according to the thermodynamic parameters(ΔHθ<0, ΔSθ>0 and ΔGθ<0). It was found that different functional group and molecular volume size of thiol surface modified reagent played an important role in the interactions between CdTe QDs and BSA.