Abstract: Systematically analyzed in the article is the association mechanism between the weld forming characteristics of the welded pipe and the quality performance. The weld geometric shape classification system is created with which the law of the influences by different weld morphologies on the mechanical properties,the metallurgical properties and the application performance are investigated. The study result identifies that it is the synergy of the welding process parameters and the process conditions that directly defines the geometric formation characteristics of the weld,and further remarkably affects the comprehensive performance thereof. Addressing the typical defects like the weld crack,relevant study is conducted,and then it is concluded that the defect occurrence rate can be improved by means of properly controlling the weld forming coefficients. Based on large amount of the process test data,the method for optimized matching of the welding parameters is proposed,which provides the theoretic basis and technical guidance for control of the weld during the actual production.