According to the requirements of full-penetration welding of marine pipe and field working conditions, a technical solution of double pass backing welding by laser-MAG hybrid welding of marine pipe was proposed. The groove assembly gap was filled by MAG welding, and then the full penetration bead was formed by laser-MAG hybrid welding. The results showed that the scheme has strong adaptability to working conditions, and can adapt to the welding under the condition of 3 mm gap and 2 mm misalignment. The front side of the weld is well formed, and the back side has uniform penetration. The mechanical properties of the welded joint were qualified and met the actual production requirements.