  We calculate the scattering amplitudes of Goldstone bosons off the
pseudoscalar D-mesons in unitarized heavy meson chiral approach. The low energy
constants appearing in $\mathcal{O}(p^2)$ chiral Lagrangian are determined by
fitting lattice simulations on $S$-wave scattering lengths. $D_{s0}^{*}(2317)$
is obtained as a bound state in $(S,I)=(1,0)$ $DK$ channel. Possible bound
states or resonance states in other channels are investigated as well. The
quark mass dependence of the mass and binding energy of $D_{s0}^{*}(2317)$ is
also investigated, which indicates predominately $DK$ molecular nature.
