Abstract: The all-position automatic welding test on two kinds of X70 steel pipes and systematical electrodes and welding process evaluation have heen made in the 2nd Pipeline Construction Company of China Oil & Gas Pipeline Bureau. In the test. 353 welded seams taken from the trial pipe section have been X-ray in spected. The test results have shown that the primary percent of pass of welded seams is up to 96. 9%, and welding time for individual welded seam is only 35 min.which is 30%-40% higher than manual welding in work efficiency. The technical features and test evaluation guidelines of this welding technology are given in this paper.