Relying on Guigang second-lane ship lock，we establish a 130 scale physical model to study the downstream lock head outlet’s flow conditions and ship berthing conditions on asymmetric and symmetric energy dissipation grille.The result reveals that adding baffle sill within the symmetric energy dissipation grille，not only the downstream approach channel flow conditions and ship berthing conditions meet the standard，but also the construction technology is simpler than the asymmetric energy dissipation grille.This study also lays a foundation for the research on the hydro-dynamics of the same type downstream lock head outlet.