S-layers, the monomolecular crystalline surface layers, have been identified in a great number of different species of bacteria and represent an almost universal feature of archaeal envelopes. Either the isolated S-layers proteins or the S-layer fusion proteins have the capability to reassemble into regular monomolecular lattices in suspension or on suitable surface and interface, which lay the foundation of S-layers in application of nanobiotechnology and biomimetics. However, when researchers are showing great interests in some macromolecules as S-Layer proteins for the self-assembly and unique physicochemical properties, they often pay little attention to the natural biological functions from macromolecules. EA1, a non-toxic protein from the S-Layer of Bacillus anthracis, not only has murein hydrolase activity, but also is an extractable antigen on the surface of Bacillus anthracis with high immunity. This study investigated the self-assembly of EA1 in vitro, and developed a kind of multifunctional nanomaterial which is based on the EA1-MPH ( methyl parathion hydrolase ) fusion protein in vitro self-assembly by smartly utilizing MPH as a marker enzyme and its function of hydrolyzing methyl parathion. As results, the biological nanomaterial produced significant advantages in pesticide degradation, enzyme storage and anthrax antibodies detection,