Abstract: Equation of state and phase transformation of ZnO in wurtzite structure and NaCl structure under high pressures are studied using density function theory(DFT) formalism.We analyze structural properties,including lattice constant,electronic density of states and band gap.The results are in good agreement with experimental and other theoretical results.It is found that the calculated phase trasformation pressure of metallic oxides using local density approximation(LDA) is generally higher than experimental results.Calculated results using generalized gradient approximation(GGA) are in good agreement with experiments.