  New physics could be explored through loop effects by the precision
measurements at the Circular Electron Positron Collider due to its clean
collision environment and high luminosity. In this work, we focus on two dark
matter models that involve additional electroweak fermionic multiplets. We
calculate their one-loop corrections to five processes, i.e. $e^+e^- \to
\mu^+\mu^-, ~Zh, ~ZZ, ~W^+W^-$, and $Z\gamma$, and investigate the
corresponding signatures at CEPC with the projected sensitivity. We find that
the detectable parameter regions of these processes are complementary. The
combined analysis shows that the mass of dark matter $m_{\chi^0_1}$ in these
two models can be probed up to $ \sim 150~\mathrm{GeV}$ and $\sim 450$ GeV at a
95\% confidence level, respectively.
