The invention discloses a hardware fitting for detecting mechanical property of a bar material and a using method thereof. The hardware fitting comprises a base, a pressure block, a core rod and an internal conical thread nut, wherein the upper end of the core rod is in threaded connection with the base; the pressure block is clamped together with a clamping groove on the base through a chuck on the upper part of the pressure block; the inner side of the pressure block is a concave surface and corresponds to a convex surface clamping region on the outer side of the core rod; an inner layer liner and an outer layer liner are arranged between the pressure block and the convex surface clamping region which corresponds to the pressure block; a plurality of pressure blocks are matched to form a hollow inverted conical platform body; and the lower part of the inverted conical platform body is provided with an external conical thread which is threaded with the internal conical thread nut. The hardware fitting for detecting mechanical property of the bar material and the using method thereof, disclosed by the invention, are used for detecting the mechanical property of the bar material. Tests prove that the hardware fitting has high operability, and is easy and convenient to manufacture. A test piece obtained by using the hardware fitting has reliable mechanical property data.