We investigate the interaction between flat membrane and point-like graviton in the plane-wave matrix model. The one-loop effective potential in the large distance limit is computed and is shown to be of r^{-3} type where r is the distance between tw
o objects. This type of interaction has been interpreted as the one incorporating the smearing effect due to the configuration of flat membrane in plane-wave background. Our result supports this interpretation and provides one more evidence about it.
