In this paper, we demonstrate a facile and one-step ultrasonic method to synthesize the bimetallic platinum ruthenium nanoparticles supported by carboxylate functionalized multi-walled carbon nanotubes (PtRu/c-MWNTs) catalyst. The results show that the atomic Pt:Ru ratio is approximately 1:1, and the Pt mass loading in catalyst is 8 %. In addition, PtRu nanoparticles with bimetallic structure, ultrasmall size (1.9 nm), and uniform distribution were well-dispersed onto the surface of c-MWNTs, which exhibit enhanced electrocatalytic performance toward methanol oxidation. It is found that this catalyst has much higher electrochemical active surface area (ECSA) (133.2 m2 gPt-1) and current density for methanol oxidation (1236.0 mA mgPt-1) than those of commercial Pt/C (20 wt.%) (55.6 m2 gPt-1, 214.2 mA mgPt-1). Furthermore, the oxidation current density of PtRu/c-MWNTs catalyst at 10000 s is 22.5 mA mgPt-1, which indicates a long-term high electrocatalytic activity of PtRu/c-MWNTs catalyst for methanol oxidation in acid media.