Preparation of SBA-15 supported palladium nanoparticles by H-2-assisted chemical reduction of a new phenylic precursor dichloro(1,10-phenanthroline) palladium(II) with supercritical carbon dioxide deposition was studied in mild conditions. The solubility study of the precursor in supercritical carbon dioxide was measured under various pressure at 353 K in order to optimize the operating parameters for the metal deposition study. The deposition experiments were performed under 17.2 MPa pressure at 353 K within 8 h. It was found that homogeneous well-dispersed Pd nanoparticles on SBA-15 with a size average of 17.05 +/- 1.79 nm determined with HR_TEM images. It was found that Pd nanoparticles deposited in the channel of the porous, into the pores and outer surface of the SBA-15 support. XRD and HR_TEM results showed that obtained Pd nanoparticles are far smaller than particles prepared by H-2 reduction method in scCO(2) in literature.