  In this paper, we calculate the scalar $a_0(980)$-meson leading-twist
wavefunction by using light-cone harmonic oscillator model (LCHO). In which the
model parameters are determined by fitting the $\xi$-moments
$\langle\xi_{a_0}^n\rangle_\zeta$ of its light-cone distribution amplitudes.
Then, the $a_0(980)$-meson leading-twist light-cone distribution amplitudes
with three different scales $\zeta= (1.0, 2.0, 5.2)~{\rm GeV}$ are given. After
constructing the relationship between $a_0(980)$-meson leading-twist parton
distribution functions/valence quark distribution function and its LCHO
wavefunction, we exhibit the $q^{a_0}(x,\zeta)$ and $x q^{a_0}(x,\zeta)$ with
different scales. Furthermore, we also calculate the Mellin moments of the
$a_0(980)$-meson's valence quark distribution function $\langle x^n
q^{a_0}\rangle_\zeta$ with $n = (1,2,3)$, i.e. $\langle x
q^{a_0}\rangle_{\zeta_5} = 0.026$, $\langle x^2 q^{a_0}\rangle_{\zeta_5} =
0.017$ and $\langle x^3 q^{a_0}\rangle_{\zeta_5} = 0.012$. Finally, the scale
evolution for the ratio of the Mellin moments $x^n_{a_0}(\zeta,\zeta_k)$ are
presented.
