Welding is an important processing method for aircraft fuel system pipelines. In order to study the welding property of fuel system pipelines, the paper uses the metallographic detection and static stretching to analyze to weld joints’ distribution and mechanical property for pipelines with two typical welding form, butt welding and intersecting welding. The weld quality grade and heat treatment method of pipelines are also taken into consideration. The main results show that: the 6061-T6 butt welding with the low quality grade has the wider heat-affected zone; the quality grade and heat treatment method show the different influence for the each zone of intersecting weld; the property of weld joint is unlike the base material zone, the tensile strength and yield strength of heat-affected zones decrease most significantly.