Cell Penetrating Peptides are a kind of small molecular peptides .These peptides are composed of 5~30 amino acid residues with the membrane penetration ability and can carry a variety of material into the cell .In this study ,we selected lactoferricin B ,4~9 residue RRWQWR (bLFcin6) ,which is a newly discovered cell penetrating peptide .We used Pymol software to build the initial structure of peptide and downloaded DPPC ,POPC and POPG membrane from website ,after the optimization ,built peptide -membrane systems .Three 500 ns long independent molecular dynamics simulations were performed with Gromacs 4 .5 .3 software .The GROMOS53a6 force field was adopted for peptide and Berger force field for membrane .The temperature was set at 323 K .For the three kinds of membrane simulation ,bLFcin6 en‐tered into DPPC membrane to the carbonyl group and interacted with the hydrophobic tail ;bLFcin6 inter‐acted with the hydrophilic head group of POPG membrane ,not into the deeper ;bLFcin6 did not contacted with POPC membrane . We analyzed the hydrogen bonds formation between different amino acids and membrane phosphate group ,found that positively charged arginine plays an important role in peptide -membranes interaction .Also ,we calculated the distance between different amino acids and the center -of-mass(COM ) of membrane ,obtained that the N end of peptide first contacted with the DPPC and POPG membranes .In addition ,the influence of different membranes to bLFcin6 is associated with the structure of lipid molecules .BLFcin6 have the different penetration ability to different bilayer membranes .Here ,it the importance of arginine is highlighted in order to consistent with previous biological experiment and simulation analysis ,it provides the reference for the further analysis of the penetration membrane process .%穿膜肽是一类由5～30个氨基酸残基组成的有穿膜能力的小分子多肽，可携带各种物质进入细胞内部，发挥各自生物学活性．bL Fcin6是一种新的细胞穿透肽，选取含有4～9个残基的 bL Fcin6为研究对象，用Py‐mol软件来构建肽的初始结构并下载膜DPPC ，POPC ，POPG的结构，在优化后搭建肽－膜的初始体系．每个体系模拟了500 ns ，对肽用GROMOS53a6力场处理，对膜用Berger力场处理，温度设置为323 K ．在这3个体系中， bLFcin6进入到DPPC的羰基端并与疏水的尾部相互作用；bLFcin6能进入到POPG的亲水头部，不能更深的插入到内部；bL Fcin6并不能接触到膜上．分析了在不同氨基酸与膜带电基团之间氢键的形成，发现了带正电的精氨酸在肽－膜之间的相互作用起了一个重要的角色．计算了在不同的氨基酸和膜的质心之间的距离，发现肽的N端首先接触到DPPC和POPG的膜上．此外，不同膜对bLFcin6穿膜能力的影响与脂质分子的结构有关．BLFcin6对不同膜有不同的渗透能力．我们重点强调了精氨酸的重要性，与先前实验和模拟中得到的结果是一致的，这为进一步探究bL Fcin6的穿膜机制提供了一定的帮助．
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