The invention relates to a fixed clamp for detecting glass, and provides a corner peripheral fixed clamp with a copper-alloy slope slide way, a conical spring and a nut. The corner peripheral fixed clamp comprises a first fixed clamp, a second fixed clamp, a third fixed clamp and a fourth fixed clamp, which are the same in structure and size, wherein each clamp is composed of a clamping part and a slippage corner part. As improvements, a slope groove is formed in one end of an upper clamping plane and a step through hole is formed in the other end of the upper clamping plane; a rotary table chamfering arc surface is formed on one side of a rotary through hole and is provided with a corner arc surface convex pointer; a slope convex rail is arranged on the other side of the rotary through hole, and a lower slippage plane and the slope convex rail can be separated; the conical spring and the knob nut are combined so that the angle can be conveniently and freely adjusted for fixing quadrilateral glass with different included angles, and the clamping parts and the slippage corner parts of the clamps can be relatively fastened to form a whole body; and the slope convex rail and the adjacent slope groove of each clamp are in sliding match, so that the fixed clamp can be continuously adjusted aiming at trapezoid glass plates with different widths.