N-phenylsulfonamido-$\alpha$-aminomethylphosphonic acid and their derivatives were prepared by the reaction of $\alpha$-aminomethylphosphonic acid with aromatic sulfonyl chlorides at low temperature(0-$5\,^\circ\!C$) in good yields. $\alpha$-amino-methylphosphonic acid was prepared by an Ivanov-type aminoalkylation of triphenylphosphite with benzylcarbamate, paraformaldehyde, and acetic anhydride. N-phenylsulfonamido-N-phosphonomethyl-$\alpha$- aminomethylphosphonic acid and their derivatives were prepared by the reaction of N-phosphonomethyl-$\alpha$-aminomethyl phosphonic acid with aromatic sulfonyl chlorides. N-phosphonomethyl-$\alpha$-aminomethylphosphonic acid was prepared from debenzylation of N,N-bis(phosphonomethyl)-benzylamine which could be obtained by Mannich reaction of benzylamine with formaldehyde and phosphorus acid. These compounds with the similar molecular skeletons to the aminophosphate herbicides are expected to have interesting biological activities.