Ternary noble metal-metalloid-nonmetal PdBS alloy mesoporous nanospheres (MSs) with three-dimensional central-radial pore channels were prepared for an electrocatalytic hydrogen evolution reaction. The synthesis was performed via precise control in the reduction and nucleation growth of ternary PdBS alloy MSs along confined cylinder mesophases assembled by amphiphilic dioctadecyldimethylammonium chloride. The resultant PdBS alloy MSs disclosed a remarkably improved electrocatalytic performance due to their structural and compositional synergies. This finding extended our knowledge on the rational design and targeted synthesis of novel noble metal-metalloid-nonmetal alloys with desired structures and morphologies for catalysis and other applications.