  According to the standard model, the Cabibbo-favored (CF) decays are $CP$
conserve at tree level. Observation of any finite $CP$ asymmetry can be
received as a signal of new physics. In CF charm meson decays, $ D^0
\rightarrow K^- \pi^+ $ and $ D^+ \rightarrow K_s^0 \pi^+ $, the following
experimental values for their $CP$ asymmetry are reported, respectively: ($0.3
\pm 0.7$) % and ($-0.41 \pm 0.09$) %. The value of the later can be attributed
to the mixing of $ K^0 $ and $ \overline{K^0} $, however, its contribution is
about ($-0.332 \pm 0.006 $) %. In this paper, we use these experimental results
to constrain the unparticle stuff as a new physics which may contribute to
these $CP$ asymmetries.
