4-((4-methylpiperazin-1-yl)methyl)benzoic acid dihydrochloride was synthesized from 4-methylbenzoic acid via α-bromination and acidification after aminnation without separation. The effects of the bromine agent and initiator on the bromination and the effects of material ratio, temperature and time on the aminnation were investigated. The optimized conditions were: bromosuccinimide as bromine agent, benzoyl peroxide as the initiator, the yield of 4-(bromomethyl)benzoic acid was close to 88.7%; the ratio of 4-(bromomethyl)benzoic acid to 1-methylpiperazine 1:1.2, sodium bicarbonate as the acid binding agent, the reaction temperature ranges from 20～25℃, the reaction time 8h., the yield of product under this optimum reaction conditions was up to 81.5%. The structure of the product was confirmed by melting point, IR and 1HNMR.