In this study, we report a single Arg9(R9) peptide translocation across a DOPC/DOPG(4:1) model membrane within an order of a few tens ns scale by using the weighted ensemble(WE) method. We identify how water molecules play a role during the translocation and show how the orientation(tilt angle) of Arg9 affects the translocation. We also observe lipid flip-flops during the simulations and show how this is related to the water flow and the translocation of peptides.