Organic/inorganic hybrid materials are the one of most dynamic research areas in materials science currently. Polyhedral oligomeric silsesquioxane (POSS) achieves the combination of organic and inorganic components at the molecular level. The structure is a three-dimensional cage type supported by the Si-O-Si bond. It has excellent reactivity, thermostability, flame resistance, porosity and nano-size effects. It could be applied in many fields after being modified. In this paper, the modification methods of POSS were described from three aspects of graft modification, polymerization modification and coordination modification. Then the application research progress of POSS in heat-resistant materials, flame-retardant materials, reinforcement materials and porous materials was reviewed. Finally, the research direction of POSS was suggested. It should be conducted on the structure-effect relationship, modification method and safety of POSS deeply and systematically to promote the application of POSS materials.