Positioning numerical control lathe fixture for machining

The utility model belongs to the technical field of numerical control lathe fixtures, and particularly relates to a positioning numerical control lathe fixture for machining, which comprises a workbench, a square tube clamping mechanism is arranged on the outer wall of the bottom of the workbench, and the square tube clamping mechanism comprises a threaded rod rotatably connected to the outer wall of the bottom of the workbench and a fixing frame screwed to the outer wall of the threaded rod. The L-shaped clamping plates can be driven to incline by rotating the threaded rod, so that a square pipe is fixed between the L-shaped clamping plates, convenience is provided for subsequent square pipe machining, meanwhile, a round pipe can be fixed between the two arc-shaped clamping plates under rotation of the bidirectional lead screw, convenience is provided for subsequent round pipe machining, and the machining efficiency is improved. The clamp can clamp pipelines of different shapes and different sizes, the appli