Nanoporous bismuth tungsten oxide (Bi₂WO₆) photoanodes are synthesized by using a facile drop‐casting strategy for one‐step fabrication. The Bi₂WO₆ photoanode exhibits significantly improved solar photo‐electrochemical capability for water oxidation. The photocurrent density is nearly 10 times higher than the traditional particle photoanodes. In addition, synchronous illumination X‐ray photoelectron spectroscopy (SIXPS) was employed to directly identify the charge separation and electron transfer in the nanoporous Bi₂WO₆ photoanodes, which clearly reveals that the electrons transfer from the Bi and W atomic sites to the O sites. These demonstrations provide further new insights into the origin of high efficiency in nanoporous photoanodes, which may be promising for the rational construction of solar conversion and storage devices.