A kind of rail-type automatic all-position pipeline welding equipment was developed. Aiming at the complex welding working conditions,the designs of key mechanism parts such as horizontal and vertical sliding blocks with sealing and dust-proof function,swing mechanism of welding gun with multi-dimensional adjustment function,rack type quick disassembly guide rail were improved. By using this automatic welding equipment,many groups of automatic GMAW pipeline welding tests were carried out,the mature welding parameters were obtained,and the macro metallographic,tensile,side bending and impact tests were carried out. The results show that this developed equipment can be used in the automatic all-position butt welding of the bridge steel tubular column. At present,this equipment has been applied in the automatic butt joint welding operation of bridge steel tubular column in the Huangling project site.