We describe a simple process for synthesizing three-dimensional porous silicon monoxide anode materials from bulk silicon monoxide powders by combining a galvanic displacement reaction and metal catalytic etching process. Silver nanoparticles that act as a catalyst were deposited on the surface of silicon monoxide via a galvanic reaction. Subsequently, the silver-deposited silicon monoxide particles were chemically etched to synthesize porous silicon monoxide particles, without changing the chemical and physical properties of SiO. The carbon-coated porous silicon monoxide anodes exhibited excellent electrochemical properties, including a high specific capacity (1520mAhg−1), a stable cycling retention (reversible capacity of 1490mAhg−1, after 50 cycles), and a high rate capability (74% at 3C rate, compared to 0.1C rate). This process may open up an effective way to make other porous semiconducting materials for a rich variety of applications, including lithium-ion batteries.