  Topological states of matter emergent as a new type of quantum phases, which
can be distinguished by their associated topological invariants, e.g., Chern
numbers. Currently, there is increasing in-terests toward the physically
detection of the new predicted topological phases. Here, we propose an
interferometric approach to directly measure the Chern number in a topological
optical lattice via detecting the associated Zak phase. We show that this
interferometric approach can distinguish Zak phases of plus or minus 2{\pi}
from 0 in the first Brillouin zone, and thus provides a new tool to directly
detect the Chern number of topological systems. In addition, we demonstrate
that this method is feasible under realistic experimental conditions and widely
applicable for many systems. Finally, this scheme can be readily generalized to
detect high Chern number systems.
