The invention discloses a reliable efficient fixture which is characterized by comprising a positioning compression cam, a press plate moving cam, a moving positioning assembly, a positioning block, acam mounting frame, a press plate assembly and an operating handle, wherein the press plate moving cam is rotationally arranged on the cam mounting frame; the rotating axis of the press plate movingcam is set along the up-down direction; the moving positioning assembly comprises a moving mounting seat and two floating press heads; the floating press heads are symmetrically arranged at two ends of the U-shaped moving mounting seat and both hinged onto the moving mounting seat; the press plate moving cam is driven by the operating handle to rotate; the press plate assembly is driven to move left and right; the positioning compression cam and the press plate moving cam are in transmission connection with each other; the moving mounting seat of the moving positioning assembly is driven by the positioning compression cam to move left and right; and then a workpiece is compressed and positioned in the positioning blocks through the floating press heads. Consequently, the press plate assembly can be driven by the positioning compression cam to compress and fix the workpiece from above.