Abstract: A modified Tersoff potential developed by extending atomic interaction distance has been applied to simulate the properties of liquid silicon by molecular dynamics. The radial distribution functions with coordination number 6.9 and bond length 0.254 nm obtained from the simulation are in good agreement with the experimental results from X-ray diffraction and neutron scattering. The presence of two peaks, ～57° and ～102°,in bond angle probability distribution indicates a very complicated structure in liquid silicon. The configurations simulated show that a chain-network structure is formed among silicon stoms in liquid silicon, and a majority of atoms remain tetrahedral local structure with near-neighbour atoms.