Abstract: This article delves into the welding performance of 316LN austenitic stainless steel in ultra-low temperature service environments. The focus is on comparing the Charpy impact properties of gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW) at liquid helium temperature (-269℃). Additionally, the performance of manual GTAW welded joints using imported and domestic welding wires is analyzed, along with the influence of different welding positions on the performance of SMAW welded joints. The results indicate that both welding methods meet the requirements for ultra-low temperature service, but exhibit distinct differences in low-temperature toughness.This work provides critical technical references for manufacturing ultra-low temperature pressure vessels and installing pressure pipelines.