Abstract: During the natural gas transmission of Jinsha lines, it generated the salt crystallization which influenced operations of cleaning pipeline. Research was conducted aiming at gas intake from gas field upstream and natural gas transmission in Majin lines & Jinshan lines. By gathering the historical sampling report of water and natural gas in Maliu gas field, analyzing formation water and natural gas samples from the field, we found out the forming reason of halide salts in pipeline. According to the crystal types of Majin gathering and transportation system, suggestions were proposed to reduce and prevent crystallization.