The present invention discloses a gantry cutting machine for pipe and flat plate, including a cutting assembly, a plate cutting mechanism, a pipe cutting mechanism and a crossbeam. The crossbeam is provided with a transverse driving unit. The cutting assembly is connected to the crossbeam. A cutting assembly mounting base is provided with a lifting-driving unit. The transverse driving unit includes a first gear, a first rack, a first motor and a first rail. The present invention provides a gantry cutting machine for pipe and flat plate to meet the demands in the field of numerically controlled cutting and machining of pipe products, which has a simple operation and is easy to use, and the clamping is flexible, so that the processing cost of pipe products can be reduced, and cutting and machining range of the numerically controlled cutting machine can be broadened.