Free Fractionally Charged Particles (FCPs) are predicted by some theories beyond or extending to the standard model. FCPs have been widely searched for by underground and space-based experiments based on the assumption of heavy lepton-like particles. However, there is a paucity of research focusing on light-mass FCPs (LFCPs) in the sub-MeV mass range. In this work, we report a search for LFCPs in primary high-energy cosmic rays, based on observational data from the Dark Matter Particle Explorer (DAMPE) satellite. This study utilizes ten years on-orbit data of DAMPE to search for LFCPs with mass in the range of $0.2MeV/c^2$ to $1MeV/c^2$ and a charge of $\frac{2}{3}e$. No LFCP candidate is observed. The upper flux limit of LFCPs with a mass of 0.5 MeV$/c^2$ and a charge of $\frac{2}{3}e$ is determined to be $\rm 5.0 \times 10^{-11}\,cm^{-2}sr^{-1}s^{-1}$ at the $\rm 90\%$ confidence level.