This investigation utilizes porous silicon as the gas diffusion layer (GDL) in a micro fuel cell. Pt catalyst is deposited on the surface of, and inside the porous silicon, to improve the performance of a fuel cell, and the Pt metal that remains on the rib is used to form a micro thermal sensor in a single lithographic process. Porous silicon with Pt catalyst replaces traditional GDL, and the relationships between porosity and pore diameter, and the performance of the fuel cell are discussed. In this work, electrochemical etching technology is employed to form porous silicon to replace the gas diffusion layer of a fuel cell. This work focuses on porous silicon with dimensions of tens of micrometers. Porous silicon was applied to the gas diffusion layer of a micro fuel cell. Boron-doped 20 '-cm n-type (100)-oriented doubly polished silicon wafer was used on both sides. The process is performed to etch a fuel channel on one side of a silicon wafer, and then electrochemical etching was adopted to form porous silicon on the other side to fabricate one silicon wafer that combines porous silicon with a fuel channel on a silicon wafer to minimize a fuel cell. The principles on which the method is based, the details of fabrication flows, the set-up and the experimental results are all presented.