The structural and thermodynamic properties of zinc-blende phase of GaN have been investigated systematically using the molecular dynamics method with Buckingham potential model. These properties including lattice constant, phase transition pressure (from the zinc-blende to the rock-salt structure), thermal expansion, isothermal bulk modulus, and heat capacity at constant pressure were calculated in a wide range of temperatures (300—3000K) and pressures (0—65GPa). The structural and thermodynamic parameters obtained under normal state are found to be in good agreement with the existing experimental and theoretical results. Meanwhile, some thermodynamic parameters such as isothermal bulk modulus and heat capacity at constant pressure have been predicted at elevated temperatures and high pressures based on the reliable potential model. The simulated results are of fundamental importance in material science.