Abstract It makes the concept of Avogadro constant easier to be understood by recognizing it from the viewpoint of basic physical constant. The first scientist who determined Avogadro constant is French physical chemist Jean Perrin. The work of determining the value of Avogadro constant has been going on for one century and still continues. Avogadro constant, amount of substance and mole have the same historic origin, different development pathway, and the same endpoint.
