  We perform hybrid Monte Carlo (HMC) simulatons of two flavors QCD with the
optimal domain-wall fermion (ODWF) on the 16^3 x 32 lattice (with lattice
spacing a ~ 0.1 fm), for eight sea-quark masses corresponding to pion masses in
the range 228-565 MeV. We calculate the mass and the decay constant of the
pseudoscalar meson, and compare our data with the chiral perturbation theory
(ChPT). We find that our data is in good agreement with the sea-quark mass
dependence predicted by the next-to-leading order (NLO) ChPT, and provides a
determination of the low-energy constants \bar{l}_3 and \bar{l}_4, the pion
decay constant, the chiral condensate, and the average up and down quark mass.
