In this work, the Five-Dynasty sky-green porcelains of the Yaozhou Kiln were studied. In order to investigate the coloring and translucency mechanism in the sky-green porcelains, we analyzed the chemical composition, phase, chemical state of the coloring elements and microstructure, using energy-dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). The results indicate that the main colorant is ferric oxide (Fe₂O₃), and that the scattering effect of the physical structures (residual crystals and phase separation droplets) can deepen or weaken the chemical color in the glaze. Furthermore, this scattering effect also affects the color saturation and opacity of glaze surfaces to some extent. Analysis of the white body indicates that the translucency is related to the absorption effect of coloring oxides and the scattering effect of crystal boundaries and residual micropores. Low contents of ferric oxide (Fe₂O₃) and ferrotitanium solid solution greatly decreased the absorption of incident light. In addition, small amounts of crystal boundaries and residual bubbles also weaken the scattering of incident light. As a result, the sky-green porcelains exhibit good translucence.