Among several different hydrogen production technologies, solar hydrogen system for water splitting is the only clean and sustainable energy supplier. Hydrogen production by water-splitting utilizing solar energy has attracted considerable interest since the pioneering work of Honda and Fujishima in 1979, who discovered that water can be photo-electrochemically decomposed into hydrogen and oxygen using a semiconductor ($TiO_2$) electrode under UV irradiation. Most efforts to utilize solar ray lead to explore visible responding photocatalysts, PEC cells and other fusion technology like bio-photocatalytic conversion. In this paper, photon utilization technologies for water splitting have been briefly reviewed except solar thermal utilization technology.