Nodular cast iron pipe with prefabricated insulating layers

The invention discloses a nodular cast iron pipe with prefabricated insulating layers. The nodular cast iron pipe comprises two nodular cast iron pipe sections connected with a spigot (1) in a sealedmanner through a bell mouth (3), two sections of inner plastic pipes (4) arranged on the outer sides of the two nodular cast iron pipe sections in a sleeving manner correspondingly, an outer plastic pipe (5) arranged on a connecting port of the two nodular cast iron pipe sections in a sleeving manner and two port insulating rubber rings (6) used for connecting the two ends of the outer plastic pipe (5) with the two sections of inner plastic pipes (4) correspondingly. Outer wall prefabricated insulating layers and connector prefabricated insulating layers are arranged between the nodular cast iron pipe sections and the inner plastic pipes (4) and between the nodular cast iron pipe sections and the outer plastic pipe (5) correspondingly. The nodular cast iron pipe with the prefabricated insulating layers is convenie