We study the superconducting state in the presence of spin-orbital coupling
and the Zeeman field. It is found that a phase transition from the
Fulde-Ferrell-Larkin-Ovchinnikov state to the topological superconducting state
occurs upon increasing the spin-orbital coupling. The nature of this
topological phase transition and its critical property are investigated
numerically. Physical properties of topological superconducting phase are also
explored. Moreover, the local density of states is calculated, through which
the topological feature may be tested experimentally.Comment: 11 pages, 8 figure