The interactions between single-chain and Gemini surfactants with hemoglobin (Hb) were extensively investigated by UV-visible spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy (CD), isothermal titration calorimetry (ITC) and Zeta potential measurements. The results demonstrated that surfactants can destroy the hydrophobic cavity of Hb, and make the alpha-helical become loose and convert it into the beta-sheet structure. The interactions between surfactants and Hb are mainly caused by electrostatic and hydrophobic interactions. The hydrophobic chain length and linking group length of surfactants have significant influence on tuning the conformations of Hb. The study provides a molecular basis for the applications of protein-surfactant complexes in biological, pharmaceutical, industrial and cosmetic systems.