The invention provides a clamp for fixing a steering knuckle in a processing process. The clamp comprises a bottom plate, wherein two bottom plate windows are processed in the bottom plate; the bottomplate windows are set to be processing parts for accommodating the steering knuckle; three groups of pressing claws and three groups of locating pins are fixedly arranged on the bottom plate; the pressing claws and the locating pins are fixedly arranged in through holes of the bottom plate separately; and the three groups of pressing claws are separately equipped on three vertexes of a triangle.According to the technical scheme adopted by the invention, the clamp has the outstanding advantages that: all processing parts of the steering knuckle can be completed on one machine tool, so that quantity demanded of machine tools is reduced, labor cost is reduced, labor intensity of a worker is relieved, auxiliary time is reduced, working efficiency is improved, and the yield returns are improved.