A method is described for incorporation of water-soluble SpA into phospholipid monolayer using covalent SPA-stearate conjugates, and then transferring the monolayer on a pre-treated silica surface to form a SpA containing membrane.Stearic acid containing a reactive N-hydroxysuccinimide ester group is synthesized,and the derivative is reacted with SpA in a deoxycholate buffer. The modified SpA (m-SpA) has the solubility properties very similar to intergral membrane proteins. The CD results show that the content of β structure in the m-SpA is incresed in lower lipid coupling degree, but in higher modification the random coli content rapidly increased. After SpA is incorporated in the DPPA monolayer, unmodified SpA is readily ejected from the monolayer but m-SpA incorporates into the monolayer stably. The incorporation of the protein is proportional to the lipid coupling degree. The IgG binding ability of m-SpA decreases with the increase of the lipid coupling degree. The ability is further reduced about 20%一30% when m-SpA is incorporated in the membrane, which might be due to the incorporating procedure.