For applications of porous silicon in energetic materials field, the reactivity of porous silicon/Pb₃O₄ modified by silane coupling agents was studied. The porous silicon used in this work was fabricated by an electrochemical etching technique and modified by KH550, KH560 and KH570, and the 10/90-porous silicon/Pb₃O₄ ignition composition was prepared. The reactive performances of the ignition composition were measured by oxygen bomb, DSC, TG and mass spectrometry. The residues after decomposition and combustion were analyzed by XRD. The results show that: (1) the heats released from samples 2, 3 and 4 modified by silane coupling agents KH550, KH560 and KH570 respectively, are higher than that of sample 1, which is not modified by silane coupling agents, but their temperatures of exothermic peaks are same, showing that the silane coupling agents just affect the kinetic behavior of decomposition reaction of the ignition composition; (2) The values of combustion heat of samples 1-4 decrease in the order: sample 2>sample 3>sample 4>sample 1; (3) the residues of all porous silicon/Pb₃O₄ after decomposition and combustion are PbO and lead silicate, respectively; (4) the KH550, KH560 and KH570, make the stability of the porous silicon in air enhance.