Similar to the water wave on a pond caused by dropping a pebble, the formation of ripples is shown in a single layer graphene ͑SLG͒ when it is stroked by a C60 molecule, no matter whether the graphene is plane or corrugated. The controllable ripple in SLG is investigated by molecular dynamics simulations. Noticeable diffraction and interference of the ripples are observed. This study indicates that the ripple propagation in graphene can be used to detect defects.