Here we described the design and synthesis of a discrete 3D amphiphilic metallacage 4, in which the tetragonal prismatic frameworks act as the hydrophobic cores and the poly(ethylene glycol) (PEG) chains as the hydrophilic tails. The structure of 4 was characterized by 1H NMR, 31P NMR and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). Notably, 4 with its long PEG tails was subsequently ordered into micelles at a low concentration (1.20×10-6 mol/L) in water. As the concentration and cultivation time increased, the micelles can further self-assembly into nanofibers and nanoribbons. Considering the dynamic property of the coordination bond, these structures show reversible transformation under extal stimuli.