Molecular Dynamics Simulations have been carried out for liquid-vapor interface of water at T=300K and ρ=1g/㎤. The system studied consists of 222 ST2 particles in a free cluster. Verlet algorithm$^1$, with Shake procedures$^2$ to handle internal constraints, is used to integrate the classical equation of motion. Orientational structuring near the surface is studied through an angle distribution function. The self-diffusion coefficients have been calculated for bulk region and for interface region. The value of bulk water is 2.87㎠/s, that of interface water is 3.11㎠/s. The significantly larger D value in the interface region can be understood qualitatively by the fact that here the water molecules form fewer hydrogen bonds than those in bulk water.