  In this Letter, a modified Chaplygin gas (MCG) model of unifying dark energy
and dark matter with the exotic equation of state $p_{MCG}=B\rho_{MCG} -\frac
A{\rho_{MCG}^\alpha}$ is constrained from recently observed data: the 182 Gold
SNe Ia, the 3-year WMAP and the SDSS baryon acoustic peak. It is shown that the
best fit value of the three parameters ($B$,$B_{s}$,$\alpha$) in MCG model are
(-0.085,0.822,1.724). Furthermore, we find the best fit $w(z)$ crosses -1 in
the past and the present best fit value $w(0)=-1.114<-1$, and the $1\sigma$
confidence level of $w(0)$ is $-0.946\leq w(0)\leq-1.282$. Finally, we find
that the MCG model has the smallest $\chi^{2}_{min}$ value in all eight given
models. According to the Alaike Information Criterion (AIC) of model selection,
we conclude that recent observational data support the MCG model as well as
other popular models.
