  We propose a scenario to create topological superfluid in a periodically
driven two-dimensional square optical lattice. We study the phase diagram of a
spin-orbit coupled s-wave pairing superfluid in a periodically driven
two-dimensional square optical lattice. We find that a phase transition from a
trivial superfluid to a topological superfluid occurs when the potentials of
the optical lattices are periodically changed. The topological phase is called
Floquet topological superfluid and can host Majorana fermions.
