High pressure&large diameter pipe fittings are used in the valve chambers and stations of long-distance gas pipelines in our country. As quality cannot be guaranteed due to bigger wall thickness by mathematical analysis, the wall thickness calculated by verification test method for imported pipe fittings are relatively thinner, which avoids the difficulty in manufacturing equipments and process and guarantees quality and safety of pipe fittings. It is explained that verification test method shall be selected for the design and calculation of pipe fittings according to comparison between imported and domestic pipe fillings in engineering projects and is proposed that foreign standards should be adopted as the basis of verification test method. Relevant technical issues in wall thickness calculation by verification methods are also discussed in this paper, including standard structure style, size and manufacturing process and specifications.