Through arranging the physical properties of the eight precious metals in accordance with their positions in the Periodic Table, three laws can be obtained： their atomic radii are close to each other and the density and specific heat nearly obey the relation of multiple proportions; melting point, boiling point, hardness and other mechanic properties vary linearly; electrical conductivity and heat conductivity vary irregularly. The cause of these three laws is analyzed by aid of the valence bond theory on the basis of atomic structure characteristics.