The influences of milling time and process control agents on the preparation of ultrafine nickel powder were studied systematically by granularity test, SEM and XRD. The results show that: with increasing milling time, the nickel powder particle size decreases rapidly at first and then the particle size changes slightly, the nickel powder can milling effectively by adding process control agent KH-570, the dispersion properties, sheet extent and the surface cleanliness are also improved. Milling 36 h the nickel powder with the process control agent KH-570 can obtain 5.76 μm high-purity nickel powder.