A Haghpeima - Physics Department, Faculty of Science, Mashhad Branch, Islamic Azad University, Mashhad, Iran

Now it is very difficult to calculate the whole hadron spectrum from first principles in QCD, under such acircumstance, various models which are QCD-based or incorporate some important properties of QCD wereproposed to explain the hadron spectrum and other low- energy properties. In this paper we will explain anddiscus some features of them.

Diquark, Hadron, Low – Energy, Multiquark Theories, Pentaquark, QCD, Quark Model