The invention discloses a natural-gas pipe welding machine. The natural-gas pipe welding machine is structurally comprises a pipe locking structure, a welding head handle, a welding controller, a welding button, a welding-ring fixing rod, a welding ring, a motor, a fixing disc, a transmission, a rotating base, supporting rods, a transverse rod, a welding clamping base, fixing rings, connecting rods and clamping supporting rods, wherein the lower ends of the clamping supporting rods are connected with the left ends and the right ends of the connecting rods in an embedded mode, the right ends ofthe fixing rings and the clamping supporting rods are integrally formed, the left ends of the connecting rods penetrate through the inner walls of the fixing rings, the connecting rods are perpendicular to the left ends of the clamping supporting rods, and the lower ends of the supporting rods and the left end and the right end of the transverse rod are welded. According to the natural-gas pipe welding machine, the pipe clamping structure is structurally arranged, an upper clamping block and a lower clamping block tightly clamp the pipe, waggling can be avoided, welding is stably carried outaccordingly, the welding effect is improved, the service life of the pipe is thus prolonged, and the use hidden danger is reduced.