In this study, yttrium-doped CeO2 was introduced into polymeric carbon nitride (PCN) through one-step hydrothermal reaction to form the Y-doped CeO2/PCN (YCC) nanocomposited photocatalysts. Morphology of products was observed by emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). The structure of the products was characterized by X-ray diffractometer (XRD), FT-IR and Raman analysis. Optical absorption and band energy properties were investigated by UV vis, PL and VB-XPS spectra. The X-ray photoelectron spectroscopy (XPS) results further revealed that the surface active oxygen and Ce3+ concentration of nanocomposited photocatalyst were significantly increased compared with pure CeO2 and PCN counterparts. The YCC composites exhibited excellent photoredox performance under visible light irradiation, affording to 5.73- and 3.74-fold higher for RhB degradation and proton photoreduction to produce H-2 than that of pure CeO2. The Y-doped nanocomposited means adopted in this study not only improve the optical utilization of visible light, but also effectively inhibit the recombination of photogenerated charge carriers, which are conducive to promote the photoredox performance synergistically.