The invention discloses a carbon brush used for a locomotive traction motor. The carbon brush is made of a soft carbon black powder, spray carbon black, a pitch coke powder, a graphite powder, a pore-forming agent, a directional auxiliary agent, modified pitch and a lubricant. The carbon brush is characterized by under a heating condition, carrying out mixed extrusion processing on the soft carbon black powder, the spray carbon black, the pitch coke powder, the graphite powder, the pore-forming agent, the directional auxiliary agent, the modified pitch and the lubricant so as to acquire a mixed material; carrying out grinding processing on the mixed material so as to acquire a first mixed powder; mixing the first mixed powder and carrying out flaking processing so as to acquire a sheet-shaped material; carrying out smashing and grinding processing on the sheet-shaped material so as to acquire a second mixed powder; blending the second mixed powder and then pressing the power into a carbon-brush pressed shape, and then successively carrying out roasting and graphitization processing. Breaking strength of the carbon brush is high, commutation performance is good and an allowable passing current density is large. The carbon brush is suitable for a diesel locomotive traction motor and is also suitable for an electric locomotive traction motor.