The invention discloses an orthopedic external fixing device. The orthopedic external fixing device comprises two arc plates in 180-degree semicircular structures, the two arc plates are fixedly connected through three connection rods, inner lateral sides of the two arc plates are provided with cotton pads respectively, and the three connection rods are in equal-radian distribution on lateral sides of the arc plates. The lateral side of each of the three connection rods is movably sleeved with five fixing plates in uniform distribution, the inner lateral side of each fixing plate is an arc face, and the outer lateral side of each fixing plate is provided with a second fastening knobs. Each arc plate is internally provided with an arc groove, an arc rod is arranged in each arc groove and in slide connection with the corresponding arc plate through the corresponding arc groove, and the upper end of the lateral side, corresponding to each arc rod, of the corresponding arc plate is provided with a positioning knob. The orthopedic external fixing device is simple in structure, convenient to fix, adjustable according to injury areas of patients, reusable, simple in operation and convenient to use.