The invention discloses a laser cleaning system for inner wall cleaning for a pipeline. The laser cleaning system comprises a laser cleaning machine, an energy transfer optical fibre with an input end connected with the laser cleaning machine, an optical fibre locking head used for locking and protecting the end head of the other end of the energy transfer optical fibre, and with the other end connected with a laser cleaning head, a movable platform used for moving forwards and backwards, and located below the laser cleaning head, a hollow motor located at the front end of the laser cleaning head, a lens cone connection cylinder with one end used for connecting the motor and rotating, and with the other end connected with a tunable-angle lens cone, a reflector located between the lens cone connection cylinder and the tunable-angle lens cone, and a focusing lens located at the light-emitting end of the tunable-angle lens cone. The laser cleaning system disclosed by the invention is capable of completing large-angle cleaning working, flexible and convenient to operate, and capable of effectively realizing laser cleaning working for the inner wall of the pipeline.