Protein A, G and L are recombinant fusion proteins that combine all immunoglobulin binding regions of Protein A, G and L. Their binding capacity covers all immunoglobulins of host animals commonly used in biomedicine except IgY, including antibody classes such as IgG, IgM, IgA, IgE and IgD, their subclasses, and antibody fragments such as Fab, scFv and sdAb. Thus, Protein A, G, and L have the broadest immunoglobulin (antibody) binding spectrum. For specific immunoglobulin molecules, Protein A, G, and L can produce the highest binding power and maximum binding at multiple sites through synergistic effects. In addition, Protein A, G, and L specifically bind to the surface conformation sites of naturally active immunoglobulins and do not bind to denatured or inactivated immunoglobulins that have lost that natural conformation.