In this paper, the molecular dynamics (MD) simulations have been carried out to study the effects of the nanostructures on the interfacial boundary conditions at the solid-liquid interface. Simple Lennard-Jones (LJ) fluids have been simulated in the parallel-plate nanochannels using nonequilibrium molecular dynamics techniques. The structure of the solid-liquid interface has been focused and a new definition of the solid-liquid interface at the structured surface has been proposed.