With oxidized polyethylene wax (OPE) as main material, the OPE micro-emulsion was prepared by high- temperature and high-press closed emulsion method. The effects of the amount of emulsifier, the emulisifying time and emulisifying temperature on the properties of emulsion were investigated. The performance of the optimized product was tested and its application was briefly discussed. The experimental results show that the optimum conditions are: emulsifier dosage are 25% (relative OPE solid wax), emulsifying time are 1 h, emulsifying pressure are 8 MPa, emulsifying temperature are 130 ~ 135 ℃, and yellowish semi-transparent OPE microemulsion are obtained. It can be used in waterborne industrial paints with other components, which can improve the scratch resistance, friction resistance and surface tension of the emulsion.