A facile synthesis of a novel side-chain sulfonated diamine is developed. The sulfonated diamine was synthesized through two-step reactions, namely the nucleophilic substitution reaction of 2-naphthol-3,6-disulfonic acid sodium salt to 2,4-dinitrofluorobenzene followed by the reduction under SnCl2/HCl system, which gave an overall yield of 32%. The product was characterized by IR and 1H-NMR measurements. The reaction conditions of nucleophilic substitution were investigated, the results showed that the room temperature was prefer to obtain the the sulfonated dinitro intermidate with high purity of 98% and yield of 64%.