In real cell environment,as we all know,ionic charge imbalance is ever present,thus forming electrostatic potential cross the membrane.Cellular processes,including the delivery of drug,polymer,micro-and macro-molecule,may rely on transmembrane potential.A number of experimental studies demonstrate that cell-penetrating peptides(CPPs)can enter cells in an energy-independent way,which is known as direct translocation.The entry is complementary to endocytosis and featured by the rapid uptake,making CPPs as a fascinating intracellular deliver agent.The ability of CPPs that can carry drugs into cells,however,the mechanism of CPP penetrating is still unknown.Here,molecular dynamics simulation method is applied to show that transmembrane potential induced by ion imbalance plays an important role for the translocation of CPPs.Furthermore,during the translocation process,a nanoscale hydrophilic hole is found in the lipid membrane,which can facilitate CPPs transporting into cell through membrane.This findings not only interpret the mechanism of CPPs penetrating across membrane,but also demonstrate the importantce of transmembrane potential in cell activity.