Using the diamond anvil cell（DAC）method and the technology of sputtered film， photoetch and chemical etching， the conductivity of micron dimension ZnO were measured successfully under high pressure with molybdenum electrodes on DAC. The samples conductivity was minimal at 919 GPa pressure， which showed the beginning of structural phase transition from wurtzite to rocksalt. Contining compression as far as 1122 GPa， the conductivity increased rapidly and then slowly， which indicated the phase transformation pressure spot was 1122 GPa and the whole example was of rocksalt structure. In addition， it was found that the oxygen holes caused conductivity change by experimentally comparing the samples annealed at 500 ℃ in air， in argon and unannealed respectively.