A small aggregate is composed of several or tens of molecules or ions, with at least one dimension in the range from a few to dozens of angstroms. Here, we named such aggregate system as Angstrom Aggregates(AA). AA with the specific size in angstrom meter might possess unique structure activity relationship. Unlike molecular level, nano system and the bulk, AA, an aggregate in angstrom scale is firstly proposed,its arrangement in order, electronic effect, surface interaction, confinement effect, is still unclear. However, recently, the structure and activity relationship of such aggregate in angstrom scale has attracted increasing interest in many areas, such as in ionic liquids, aqueous solution,catalytic system, and bio-system. As the physical and chemical propeties of AA strongly depends on its structure, the in situ characterizzation technique combined with theoretical methods should be developed to understand the exact interaction between the component of the clusters, the assembly formations, the special features, and the reaction activities. It has great scientific meaning to detect, represent and regulate the structure and function of AA precisely, facilitating in its application. A systematic and thorough research on AA in angstrom scale will promote the development of fundamental science and the progress of technology significantly.