MacArthur & Wilson′s equilibrium theory of island biogeography and modern metapopulation theory are the two main theories applied in biodiversity conservation and reserve planning. The difference between the two theories was usually noticed. However, it was seldomly regarded that the conceptions of the two theories were tangibly connected, and the two theories had the same origin. Because there were frequent and close contacts between Levins and MacArthur, we wrote a letter to R. Levins, the creator of metapopulation theory, in August, 2005, and requested him to retrospect his cooperative process with R. H. MacArthur and what effects the theory of island biogeography brought to him to put forward the idea of metapopulation. Levins gave us a detailed answer. Based on this, we compared the assumptions, main models and essences between island biogeography, classical and modern metapopulation theory. Mutispecies metapopulations and metacommunities were introduced. The application and limitation of island biogeography and metapopulation theory in conservation biology were also analyzed.