For the development of polymer based nanoscience, self-consistent field theory (SCFT) has made crucial contributions. It was originally developed by Edwards in the 1960s, and with the recent advance of computer hardware and numerical scheme, real space method and pseudospectral method are introduced and widely used nowadays. In this talk, I will present a few SCFT based researches about block copolymers, polymer brushes, nanoparticle-polymer mixtures and nanostructured thin films. For the study of formation and evolution of polymeric nanostructures, theoretical tools beyond the mean field theory are necessary, and I will also explain my efforts on this subject.