Abstract: Langevin dynamics was applied to investigate the molecular assembly formed between an all β-sheet model protein and surfactants with different hydrophobicity and concentration.It was shown that surfactants with weak hydrophobicity (ε_s≤0.20) formed a cage and thus enhanced the stability of the
entrapped protein.While surfactants with strong hydrophobicity （ε_s>0.20）formed a complex with the hydrophobic beads located in the interior region of the protein and led to the structural decomposition of the protein，i.e.，protein unfolding.The above coarse-grained simulation agreed well with experimental observations reported elsewhere.The molecular insight into the protein conformational transition，as established by the present simulation，can be used to guide the design and application of surfactant in bio-processing engineering.