An interesting radiolarian-like silica sphere has been prepared from a water-diethyl ether binary solvent system, which is characterized by SEM, TEM, XRD, and adsorption experiments. The results indicate its particular morphology and hierarchical structure, i.e., hollow interior and a crust wherein two types of mesopores with radial orientation are located. This silica product embodies a novel morphosynthesis involving unstable water-oil interface.