Porous silicon was prepared by electrochemical etching on silicon wafer with micro-electromechanical systems(MEMS). The structure of porous silicon and porous silicon explosive was characterized by scanning electron microscopy(SEM),Micromeritics ASAP 2020,differential scanning calorimetry (DSC) and Fourier transform infrared spetroscopy （FTIR),and the ignition properties of porous silicon explosives were studied as well. Results show that porous silicon has a sponge-like structure with nano-pore sizes,about 20 nm and larger specific surface area,and porous silicon explosive reacts at 515 ℃,and can be ignited with heat stimulation energy by baking 2 min and 1.6 A current,which shows that under no restrict condition, porous silicon explosive can be ignited by heat and eletricity energy.