This article presents a simple method for the fabrication of shape-controllable Ni complex particles via an AOT-based single microemulsion. In this approach, Ni2+/N2H4/EG solution is used as the dispersed phase, and cyclohexane is used as the continuous phase to obtain a microemulsion by the aid of the anionic surfactant ACT. The primary Ni complex particles with diameters of 20-30 nm were first formed in the reverse micelles and then self-organized into spindle-like, ellipse-like, cuboid, and cubic morphologies, depending on the reaction conditions. When aged at 100 degrees C for 24 h, these Ni complex particles changed into crystalline Ni. A possible evolution mechanism of the Ni complex particles with different morphologies is also discussed.