Abstract: The main methods of preparing MgO thin films,including Electron-beam evaporation,Magnetron sputtering, Sol-gel,MBE and PLD were reviewed.The advantages and shortcomings of these methods in MgO film preparation are represented.The effects of different growth conditions on crystalline orientations and surface morphology of MgO thin film arc discussed.The results show that a higher rate of secondary electron emission has been gained by magnetron sputtering preparing MgO films.