Using full-potential linear-muffin-tin-orbital molecular-dynamics (FP-LMTO-MD) method, we have performed calculations on the fullerene cage structures and the binding energies of Si 3 6 cluster. It is found that their atomic arrangement tends towards tetrahedral geometry. The distorted structures are very stable. In addition, we have also investigated a stacked structure by tricapped trigonal prisms (TTP). The stacked structure is slightly more stable than the distorted fullerene cages. Their electronic states suggest that they present different electric properties.