A checking fixture for a steering knuckle. In use, a workpiece is mounted on the checking fixture, three locating points of the workpiece in the X direction respectively correspond to a supporting pin I, a supporting pin II and a supporting pin III, a locating taper hole limiting the motion of the workpiece in a YZ plane corresponds to the floating pin, and a locating point of the workpiece in the Y direction levelly fit to a supporting surface of a locating pin; after location is completed, the workpiece is tightly clamped by a jacking clamp, a press clamp I and a press clamp II. The checking fixture for the steering knuckle can measure the position accuracy of each hole of the steering knuckle workpiece, and can detect whether the relative height of the flange plane of the workpiece relative to the X-direction locating points is qualified.