The invention relates to a 
broadband radial pattern leaky 
coaxial cable used for subway and a manufacturing method thereof, and the leaky 
coaxial cable has the double functions of 
transmission line of information and 
duplexer. The structure of the leaky 
coaxial cable consists of an inner conductor, an 
insulation layer, an outer conductor and a jacket, wherein, the inner conductor is externally covered with the 
insulation layer which is externally covered with the outer conductor that is externally sheathed with the jacket, and the 
insulation layer that covers on the surface of the inner conductor adopts 
nitrogen or 
carbon dioxide physical foam to form a foamed 
polyethylene insulation layer; cambered slotted holes are opened on a 
clutch gold belt of the outer conductor covered outside the insulation layer. The manufacturing method comprises the steps: (1) a spiral 
wrinkle inner conductor is manufactured by longitudinal covering 
welding and 
embossing by using a 
copper strip; (2) the 
nitrogen or the 
carbon dioxide are adopted to be injected into the smelted polyvinyl plastics, and then the physical foamed 
polyethylene insulation layer is formed on the surface of the inner conductor by 
extrusion and cladding; (3) the slotted holes broken out by the 
clutch gold belt of the outer conductor are the cambered slotted holes; (4) the 
clutch gold belt of the outer conductor is covered on the insulation layer longitudinally, and the surface of the clutch gold belt of the outer conductor is crowded and covered with the jacket.