Through a large number of orthogonal experiments, a multifunctional long-life extreme pressure emulsified cutting fluid was developed by selected base oil, oily agent, extreme-pressure agent, anti-rust agent, emulsifier, biocide mildewcide etc. The stability of emulsified fluid, the particle size distribution and physico-chemical properties were tested, the four ball test, tapping torque test and cast iron antirust test were performed. The results show that the developed fluid has good storage and dilution stability, excellent lubricity and antirusting properties and uniform particle size distribution. With the characteristics of multifunctional and long service life, the developed fluid can be used for the processing of ferrous metals(cast iron, carbon steel, alloy steel, stainless steel ) and nonferrous metals(copper, aluminum and its alloy), which can meet the requirements of milling, drilling, boring, tapping, broaching and other processes.