The invention discloses a four tube-single tube switching joint for narrow-foundation steel tube poles. The switching joint is used for connecting a single-tube steel tube pole with a four-tube steel tube pole in a power transmission and distribution line. The switching joint is characterized by comprising an upper connecting module, a body and four lower connecting modules which are welded in sequence, wherein the four lower connecting modules are evenly distributed at the bottom of the body. The switching joint has the advantages that the switching joint is simple in structure, attractive in appearance, small in occupied space, clear and definite in force transmission and suitable for power transmission line projects in urban areas; compared with the traditional single-tube steel tube pole, a novel steel tube tower with the joint is large in overall rigidity, tower top displacement can be effectively reduced, and the project quantity of the iron tower and a foundation can be reduced to save resources; compared with the traditional four-tube steel tube pole, the novel steel tube tower with the joint saves steel and has great economic benefits.