Using an effective interionic interaction the properties of vitreous and molten GeSe 2 are investigated by molecular dynamics method (MD). The effective interaction includes steric repulsion, Coulomb interactions due to charge transfer, and charge-dipole interaction due to large electronic polarizability of anions. Calculations are carried out on systems consisting of 648 and 5184 particles. Results for partial pair distribution functions, static structure factors, distribution of bond angles, and vibrational density of states are calculated at various temperatures in the molten and glassy states. Short range order in both glassy and molten states is dominated by Ge(Se 1 2 ) 4 tetrahedra and Ge-Se, Se-Se and Ge-Ge bond lenghts are found to be 2.35, 3.75 and 4.30 Å, respectively. The static structure factor exhibits the first sharp diffraction peak (FSDP), a characteristics of intermediate range order in chalcogenide glasses, as well as all the other peaks observed in X-ray and neutron diffraction measurements. We have also calculated the anomalous temperature dependence of the first sharp difraction peak. From a detailed analysis of partial distribution functions we determine that Ge-Ge correlations around 10 Å and Ge-Se correlations around 6 Å are responsible for the FSDP. The calculated vibrational density of states in the glass shows peaks at 8.0, 10.8, 26.4, 34.4 and 37.2 meV, which are all in good agreement with inelastic neutron scattering experiments. In addition, the companion line ( A 1c) of the symmetric breathing mode A 1 (26.4 meV) is identified with a feature at 27.8 meV in the density of states. Raman scattering studies also find the companion line to be ∼ 1.5 meV higher than the symmetric breathing mode.