The research on the biological stability of drugs is mainly limited to the anti-enzymatic hydrolysis ability of biological agents such as proteins, peptides and enzymes. For example, l-asparaginase is one of the earliest protein macromolecular biochemical drugs, which is mainly used in acute lymphoblastic leukemia.However, as a kind of enzyme protein preparation, the stability of the drug affects and limits its clinical application to a certain extent.The thermal stability and antitrypsin hydrolysis ability of l-asparaginase -cd inclusion compound were studied after lyophilization. The results showed that -cd can significantly increase the stability of drug and is a good enzyme protectant.Cyclodextrin protein drugs protection reasons might be: protein molecular surface distribution of polar amino acid residues, the polarity of these residues side chain with beta CD molecules form hydrogen bond of hydroxy, thus embedded in the beta CD's mouth water,?or?residue side chain insert beta CD internal tubular structure, side chain alkyl chain in the hydrophobic bonding and beta CD molecular interactions, the hydrophobic portion of space hole side chain at the same time outside the polar groups and beta CD molecules at the mouth of the close water to form hydrogen bond, forming a stable clathrate.In addition, cyclodextrin can also solve the biological products in water easy to form a dimer, polymer,?or?easy to be the container wall non-specific adsorption caused by the biological sample activity reduction and other problems.