Using a SiO2 supported copper and H4SiW12O40 catalyst, it is demonstrated that glycerol can be directly converted to 1,3-Propanediol (1,3-PD) through vapor-phase process under pressure below 0.54 MPa, without employing environmentally harmful organic solvent. The formation of 1,3-PD is proved to proceed through the designed reaction pathway: (step 1) dehydration of glycerol to 3-hydroxypropanal on acid site of supported H4SiW12O40 (step 2) hydrogenation of 3-hydroxypropanal on supported copper metal. The effect of temperature, weight hourly space velocity, pressure, and initial water content was investigated to obtain the optimum conditions. The glycerol conversion and products distribution greatly depended on these factors. Both the 1,3-PD and 1,2-Propanediol selectivity improved with increasing hydrogen pressure. At 210 A degrees C, 0.54 MPa and 83.4% conversion, the selectivity of 1,3-PD was up to 32.1%, together with a 22.2% selectivity of 1,2-Propanediol. The cyclic acetal, an important kind of byproducts, was identified by Gas Chromatogram-Mass Spectrometer (GC-MS).