Based on the conservative sequences, topological, biochemical, physiological and immunological data of anion exchanger (AE, band 3 protein) families, a peptide included 12 amino acids (position 476～487: SKLIKIFQDYPL) was synthesized and the antibodies against this peptide and the native segment of band 3 from rat erythrocyte membrane were prepared. The findings of immunoblotting and anion transport studies indicated that the peptide is an essential segment of the anion transport which is a conservative sequence in mammals (rat, mouse as well as human). Immunoscanning electron microscopic study proved directly that the peptide is located at the peripheral domain of band 3 in rat erythrocyte membrane. The antibodies against band 3 are useful tools in studying the structures and functions of the anion transport protein and investigating the relationship between band 3 and diseases.