NOVELTY - A free base tetramisole is synthesized by pumping 30% hydrochloric acid to a hydrochloric acid head tank, pumping 98% concentrated sulfuric acid to concentrated sulfuric acid head tank, closing all the valves of chlorination pot, opening manhole, adding 110-120 pts.wt. hydroxysalt, e.g. N-chloro-N-(2-hydroxy-2-phenethyl)amine hydrochloride, and 60 pts.wt. edible salt, and adding 110-120 pts.wt. water.    USE - Method for the synthesis of free base tetramisole (claimed).    ADVANTAGE - The method increases yield, reduces consumption of raw material, thus reducing production cost, improves competitiveness of enterprises, fills domestic gap, conserves energy, reduces emission, and provides environmental protection.    DETAILED DESCRIPTION - Synthesis of free base tetramisole comprises:    (A) pumping 30% hydrochloric acid to a hydrochloric acid head tank, pumping 98% concentrated sulfuric acid to concentrated sulfuric acid head tank, closing all the valves of chlorination pot, opening manhole, adding 110-120 pts.wt. hydroxysalt and 60 pts.wt. edible salt, and adding in 110-120 pts.wt. hydroxysalt, e.g. N-chloro-N-(2-hydroxy-2-phenethyl)amine hydrochloride, where mass ratio of hydroxysalt and salt is 220-240:60;    (B) closing the manhole, taking 60-100 pts.vol. hydrochloric acid from hydrochloric acid head tank, stirring, and putting hot water through the chlorination pot layer to heat;    (C) adding 110-150 parts by volume concentrated sulfuric acid from concentrated sulfuric acid head tank at speed of 30-50 pts.vol./hour after heating at 40-45 degrees C, controlling the reaction temperature at 41-46 degrees C, and adjusting the pressure at 1.3-1.5 kg/cm2 for 3-3.5 hours;    (D) heating at 50-55 degrees C, preserving heat for 1.5-3 hours, finishing the chlorination reaction, slowly sending in the hydrogen chloride into the recovery tower to absorb, and discharging the feed liquid by the valve at the bottom of the pot into neutralization pan to neutralize;    (E) adding 1300-1700 pts.vol. tap water, 700-1000 pts.wt. caustic soda liquid, 200-300 pts.wt. methylbenzenes and 200-300 pts.wt. n-butyl alcohol into neutralization pan, and putting cold liquid to cool at 10-15 degrees C;    (F) placing in the obtained chlorination material, detecting pH to keep the pH at 9.7-10, controlling at 50-55 degrees C, preserving heat for 25-30 minutes without changing the pH, detecting and adjusting the pH; and    (G) finishing the neutralization reaction, adding in 80-150 pts.vol. of 30% hydrochloric acid salt, layering, and obtaining the tetramisole.