The Hongshui river in Guangxi has a wide river surface, rapid water flow and prominent karst landforms, which imposes stringent requirements on the construction technology and safety management of long-distance gas pipelinein construction of immersed pipeline crossing.In order to improve the construction effect of long-distance gas pipelinein construction of immersed pipeline crossing under karst landform and achieve the construction of immersed pipeline crossing safely and smoothly,Guangxi natural gas pipeline project combines the unique of karst topography in Hongshui river and the influence of various factors on various stages of construction,the project gets a comprehensive and detailed analysis of the key points of safety control,proposes more scientific management measures,and does a good job of safety control over the entire process of construction of immersed pipeline.Combining with its construction management experience, this paper mainly analyzes five aspects of welding, drifting pipe, immersed pipe, lifting operation and equipment personnel, summarizes the key points of safety control in construction of immersed pipeline crossing large river in karst landform conditions, and summarizes scientific management measures. It provides a reference for the construction and safety management of immersed pipes with similar geological conditions.