The invention discloses an integrated automatic plasma cutting and welding device, which comprises a base, a positioning mechanism and a cutting and welding mechanism. Matching support seats are welded at the top end of the base at the front, rear, and middle sections on both sides, and the top surfaces of the two matching support seats are in the shape of a Arc-shaped structure, the positioning mechanism includes two arc-shaped positioning plates, two hinge rods, a first connecting rod and a second connecting rod, the middle section of the right end surface of the base is horizontally provided with a support block that is flush with the top surface of the base, The cutting and welding mechanism includes a supporting column, an adjusting frame, a first regulating plate, a second regulating plate and a plasma cutting and welding device. The invention facilitates accurate positioning of the position of the axle housing during the cutting and welding operations, is not prone to dislocation during cutting and welding, improves the accuracy of cutting and welding, reduces the defective rate, and reduces the operator's investment at the same time. Production efficiency is significantly improved.