The invention provides a test tube clamping device. The test tube clamping device comprises an operation ring, clamping rings, a movable rod and transverse rods, wherein the operation ring is a cylindrical ring which is arranged vertically, and the bottom edge of the operation ring is correspondingly provided with a fixing ring; the transverse rods are horizontally arranged above the fixing ring; the movable rod penetrates through the fixing ring in the vertical direction; each clamping ring is a circular-arc-shaped ring with an angle smaller than 180 degrees; the two clamping rings are horizontally and oppositely arranged; the corresponding transverse rods are arranged on the two clamping rings respectively; flat teeth are arranged on the two transverse rods; semi-gears engaged with the flat teeth are arranged in the middles of the flat teeth; a pull ring is arranged at the arc top of each clamping ring; sleeve rings of the end parts of the transverse rods sleeve a top sleeve ring of the movable rod, and the pull rings sleeve a bottom end sleeve ring of the movable rod; and the difference between radians of smooth surfaces of the semi-gears corresponding to the two transverse rods is 15 degrees-60 degrees.