  We construct a topological sigma model and a current algebra based on a
Courant algebroid structure on a Poisson manifold. In order to construct
models, we reformulate the Poisson Courant algebroid by supergeometric
construction on a QP-manifold. A new duality of Courant algebroids which
transforms H-flux and R-flux is proposed, where the transformation is
interpreted as a canonical transformation of a graded symplectic manifold.
