Magnetic nanocomposites prepared using a polyacrylamide gel method have been widely investigated recently for applications including high temperature superconductors and solid oxide fuel cells. The polyacrylamide gel method is an effective way to prepare diverse microstructures such as nanoparticles, nanorods and porous monolithic structures, etc. using organic monomers including acrylamide and bis-acrylamide etc. and the appropriate chelating agents. This paper reviews recent development of the polyacrylamide gel technology for synthesis of magnetic nanocomposites, focusing on the following nanostructures: (1) 0D nanoparticles (NPs) dispersed in a hollow spheres matrix; (2) core/shell structure; (3) 2D nanosheets dispersed in a bulk matrix; and (4) 0D nanoparticles (NPs) dispersed in a porous matrix. By appropriately selecting chelating agents/initiators and controlling the unique physicochemical properties of the magnetic nanocomposites, various types of nanocomposites based on nanoparticle, nanorods, nanowires and nanowhiskers can be assembled and synthesized, which are promising for new intriguing applications such as magneto-optic and magneto-electronic applications.