p-hydroxy phenyloctadecanol and p-hydroxyphenyloctadecanoic acid were used as new precursors for the preparation of surface active hydroxamic acid including different moles of propylene oxides. The hydroxamic acid was prepared by the reaction of propenoxylated products with sodium chloroacetate, followed by methyl esterification and the resultant product reacted with hydroxl amine hydrochloride to give the hydroxamic acid. the structures of the prepared hydroxamic acid were confirmed by spectroscopic study. the surface activity of prepared hydroxamic acid was studied , the results reveals that the prepared hydroxamic acid has pronounced surface activity, the alcohol substrate shows a surface activity superior than the acid substrate.