The invention discloses a high-precision cutting device for a stainless steel round pipe. The high-precision cutting device comprises a bottom plate. Supporting frames are welded to the two sides of the upper end of the bottom plate. A top plate is welded to the top end of the supporting frame. Lead screws are mounted on the left side of the rear end and the right side of the front end of the topplate. Upper lifting blocks are mounted in the middles of the upper ends of the lead screws through left-hand threads. Lower connecting rods are hinged to the inner sides of the upper lifting blocks.Lower lifting blocks are mounted in the middles of the lower ends of the lead screws through right-hand threads. Upper connecting rods are hinged to the inner sides of the lower lifting blocks. Limiting frames are mounted in the middles of the inner sides of the supporting frames. Limiting grooves are mounted in the inner sides of the limiting frames. Limiting columns are hinged to the middles ofthe upper connecting rods and the middles of the lower connecting rods in a cross mode and arranged in the limiting grooves. Limiting rings are mounted on the inner sides of the limiting grooves. Fixing columns are mounted at the upper ends of the middles of the bottom plates. Fixing plates are mounted at the upper ends of the fixing columns. A cutting hydraulic cylinder is mounted at the upper end of the middle of the top plate. According to the high-precision cutting device, an upper clamping block and a lower clamping block can clamp and fix the steel pipe up and down and left to right in the front position and rear position, and manual pressing fixing is avoided.