The invention discloses a PtRu binary 
metal nano-
alloy catalyst which is of a flower-shaped (porous) structure. The synthetic method of the PtRu binary 
metal nano-
alloy catalyst is characterized by comprising the steps that 1, a surface 
active agent and a 
reducing agent are added into water together, and stirring is conducted for 10-30 minutes at the indoor temperature, wherein the 
mass ratio of the surface 
active agent to the 
reducing agent is 1:2-2:1, and the amount of added water needs to meet the requirement that both the surface 
active agent and the 
reducing agent are completely dissolved in the water; 2, a metallic 
platinum salt pecursor solution and a metallic 
ruthenium salt pecursor solution are added in the 
mixed solution obtained in the first step, and stirring is conducted for 10-30 minutes at the indoor temperature,wherein the volume ratio of the 
platinum salt pecursor solution to the metallic 
ruthenium salt pecursor solution is 3:2-2:3, the ratio of the volume of the 
mixed solution to the total volume of the metallic pecursor solutions is 10:1-20:1, and the concentration of the 
metal salt precursor solution is 0.05-0.5 mol / L; 3, the 
mixed solution obtained in the second step is stirred for 5-30 minutes at the indoor temperature, a reaction is conducted in an 
autoclave for 1.5-3 hours, and the temperature is controlled to be 180-230 DEG C; 4, the product obtained in the third step is cooled and then is washed, and the PtRu binary metal nano-
alloy catalyst of the flower-shaped (porous) structure is obtained after 
centrifugal separation.