  We report constraints on the dark photon effective kinetic mixing parameter
(${\kappa}$) with data taken from two ${p}$-type point-contact germanium
detectors of the CDEX-10 experiment at the China Jinping Underground
Laboratory. The 90\% confidence level upper limits on ${\kappa}$ of solar dark
photon from 205.4 kg-day exposure are derived, probing new parameter space with
masses (${m_V}$) from 10 to 300 eV/${c^2}$ in direct detection experiments.
Considering dark photon as the cosmological dark matter, limits at 90\%
confidence level with ${m_V}$ from 0.1 to 4.0 keV/${c^2}$ are set from 449.6
kg-day data, with a minimum of ${\rm{\kappa=1.3 \times 10^{-15}}}$ at
${\rm{m_V=200\ eV/c^2}}$.

High Energy Physics - Experiment;High Energy Physics - Phenomenology;Instrumentation and Detectors