A powdered photocatalyst and manufacturing method thereof are disclosed. The manufacturing method of the photocatalytic nanopowders is achieved by the non-transferred DC plasma apparatus in an atmosphere of nitrogen at around 1 atm. The nitrogen-containing gas is used as the plasma-forming gas. After the generation of the nitrogen-plasma in the non-transferred DC plasma apparatus, a plurality of solid Zn precursors are introduced to the nitrogen-plasma for vaporization and oxidization. The solid Zn precursors are vaporized and oxidized through homogeneous nucleation and are rapidly cooled down by a large amount of cooling gas (i.e. mixture of nitrogen and oxygen). After the cooling process, the tetrapod-shaped and nitrogen-doped photocatalytic ZnO nanopowders having wurtzite structure are formed.