  We propose in this paper a new model for describing the unification of dark
energy and dark matter. This new model is a further generalization of the
generalized Chaplygin gas (GCG) model, thus dubbed new generalized Chaplygin
gas (NGCG) model. The equation of state of the NGCG is given by $p = -
\tilde{A}(a)/\rho^{\alpha}$, where $a$ is the scale factor and
$\tilde{A}(a)=-w_XAa^{-3(1+w_X)(1+\alpha)}$. We show that the NGCG model is
totally dual to an interacting XCDM parametrization scenario, in which the
interaction between dark energy and dark matter is characterized by the
constant $\alpha$. We discuss the cosmological consequences led by such an
unified dark sectors model. Furthermore, we perform a statefinder analysis on
this scenario and show the discrimination between this scenario and other dark
energy models. Finally, a combined analysis of the data of Type Ia supernovae,
cosmic microwave background, and large scale structure provides a fairly tight
constraint on the parameters of the NGCG model.
