A novel nanostructure of [CoFe2O4/PVP]//[YAG:7 % Tb3+/PVP] magnetic-luminescent bifunctional Janus nanofibers has been successfully fabricated via electrospinning technology using a homemade parallel spinneret. Electrospun YAG:7 % Tb3+ luminescent nanofibers and CoFe2O4 magnetic nanofibers were respectively incorporated into polyvinyl pyrrolidone (PVP) matrix and electrospun into Janus nanofibers with CoFe2O4 magnetic nanofibers/PVP as one strand nanofiber and YAG:7 % Tb3+ luminescent nanofibers/PVP as another strand nanofiber. [CoFe2O4/PVP]//[YAG:7 % Tb3+/PVP] magnetic-luminescent bifunctional Janus nanofibers possess superior magnetic and luminescent properties due to their peculiar nanostructure, and the luminescent characteristics and saturation magnetizations of the Janus nanofibers can be tuned by adding various amounts of YAG:7 % Tb3+ luminescent nanofibers and CoFe2O4 magnetic nanofibers. Compared with CoFe2O4/YAG:7 % Tb3+/PVP composite nanofibers, the magnetic-luminescent bifunctional Janus nanofibers provide higher performances due to isolating YAG:7 %Tb3+ luminescent nanofibers from CoFe2O4 magnetic nanofibers. Formation mechanism of [CoFe2O4/PVP]//[YAG:7 % Tb3+/PVP] Janus nanofibers is also presented. The design conception and construction technology are of universal significance to fabricate other bifunctional Janus nanofibers.