Abstract: With the continuous development of welding equipment and technology, the application of automated welding technology is becoming increasingly widespread. For long-distance pipelines with relatively single materials and specifications, it is more conducive to the development of automatic welding. This article summarizes the downward welding automation welding technology based on the process research of newly introduced long-distance pipeline internal and external welding machines. The obtained welding joint performance meets the standard requirements, and this welding process has been applied in actual project construction, achieving good welding results.