  In this work, we investigate the massive Kane-Mele model for graphene in the
presence of disclination and an external magnetic field, where graphene
behaviors as a topological insulator. In the low-energy limit, the effective
field equation for graphene is described by a Dirac equation with three
different degrees of freedom. We succeed to decouple the set of eight
components of the Dirac equation by using the spin projector \hat{C} in the
disclinated geometry. As consequence, we obtain the Landau levels in this
framework, in which we note the emergence of zero modes as edge states due to
the inversion symmetry breaking. We also note that for different sites in
sublattices \mathcal{A/B}, one can have different values of gap width.
