The invention discloses a clamping device for steel pipe machining. The clamping device for steel pipe machining comprises a base plate. A positioning clamping assembly is arranged at the position, close to the left side, of the top of the base plate. A vertical plate is arranged on the right side of the top of the base plate. A threaded hole is formed in the vertical plate, and a pushing threaded rod is arranged in the threaded hole in a matched mode through threads in the threaded hole. A first rotary handle is arranged at the right end of the pushing threaded rod. A pushing plate is arranged at the left end of the pushing threaded rod. A bracket is arranged at the top of the base plate and located between the positioning clamping assembly and the vertical plate. An annular bearing groove used for supporting a steel pipe is formed in the top of the bracket. The clamping device is simple in overall structure, the steel pipe can be clamped and fixed through cooperation between a first clamping wheel and a second clamping wheel, and after the steel pipe is clamped and fixed, the first clamping wheel and the second clamping wheel can rotate to drive the steel pipe to move.