We describe the synthesis and characterization of amorphous micro/mesoporous xerogels using mixed polymethylhydrosiloxane (PMHS) and tetraethyl orthosilicate (TEOS) as the inorganic source in the presence of ethyldiamine (EDA) as catalyst via a controllable sol-gel route, without additional introduction of any structure-directing agent. The results materials were thoroughly characterized by X-ray diffraction (XRD), nitrogen adsorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and 29Si MAS NMR. It was interestingly shown from these characterization results that the present amorpours samples exhibited disordered pore structure, high specific surface areas and pore volumes, though neither solvent extraction nor calcination was utilized. More interestingly, the relative content of micropore and mesopore could be finely tuned by facilely adjusting the mass ratio of PMHS to TEOS.