Nano-sized hollow-CdS@g-C3N4 core-shell spheres with different g-C(3)N(4 )contents were synthesized by a combined ultrasonication and chemisorption method. The materials were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopic (XPS) and UV-vis diffuse reflection spectroscopy (UV-Vis), etc. The photocatalytic hydrogen production activities of these hollow core-shell spheres were evaluated in water under visible light illumination with Na2S and Na2SO3 as sacrificial reagents. Material characterizations showed that g-C(3)N(4 )was moderately coated on CdS hollow nano-spheres with intimate contacts. It was found that the g-C(3)N(4 )coating could significantly improve the photocatalytic hydrogen production rate of pure hollow CdS nano-spheres and g-C(3)N(4 )coating content of 5 wt% produced the highest hydrogen evolution rate. It is proposed that the synergistic effect of CdS core and g-C3N4 shell effectively promotes the charge separation and facilitates the transfer of corrosive holes from CdS to more robust C3N4, and therefore results in enhanced photocatalytic activity and photo-stability.