In this paper,the wetting eroding properties of MgO films,used as sacrificial layer materials,was researched in H₃ PO₄ solution,including the transverse eroding speed and vertical eroding speed. The relationships between the eroding speed of MgO films in H₃ PO₄ solution and the temperature and concentration of H₃PO₄ solution were obtained,and the better technical parameters were obtained for the manufacturing of the MgO films graphs and the holding structure in which MgO is used as sacrificial layer materials.