  The generalized tight-binding model is developed to investigate the
magneto-electronic properties in twisted bilayer graphene system. All the
interlayer and intralayer atomic interactions are included in the Moire
superlattice. The twisted bilayer graphene system is a zero-gap semiconductor
with double-degenerate Dirac-cone structures, and saddle-point energy
dispersions appearing at low energies for cases of small twisting angles. There
exist rich and unique magnetic quantization phenomena, in which many
Landau-level subgroups are induced due to specific Moire zone folding through
modulating the various stacking angles. The Landau-level spectrum shows
hybridized characteristics associated with the those in monolayer, and AA $\&$
AB stackings. The complex relations among the different sublattices on the same
and different graphene layers are explored in detail.
