Abstract: A clamping device includes: a clamp assembly and an adjustment assembly, the clamp assembly comprises two symmetrical clamp arms which are oppositely hinged to each other. Each of the clamp arms includes two identical and parallel clamp pieces, and a jaw, the jaw is detachably connected between the two clamp pieces, a lower edge of the jaw includes, in order from left to right, a first arc-shaped section, a second arc-shaped section and a horizontal section, the bottoms of the first arc-shaped section, the second arc-shaped section and the horizontal section are at a same plane, the first and second arc-shaped sections are symmetrical to each other, an angle is defined between the first and second arc-shaped sections, a V-shaped groove is defined between the second arc-shaped section and the horizontal section, and the first and second arc-shaped sections are each longer than the horizontal section.