The nitration of benzene in an unbaffled glass reactor with 0.15 m in diameter,0.375 m in height and 0.0065 m3 with capacity was investigated systemically in our experiments.The results showed that solubility of nitrobenzene in the acid phase depended strongly on the molar ratio of sulfuric acid and nitric acid.As the molar ratio of sulfuric acid and nitric acid increased,the solubility increased tremendously.The surface tension,however,decreased with increase in the molar ratio of sulfuric acid and nitric acid.It was also found from experiments that the yield of 1,3-Dinitrobenzene was very low as the molar ratio of sulfuric acid and nitric acid was from 3.8 to 4.7.When the molar ratio of sulfuric acid and nitric acid was more than 5.3,the yield and concentration of 1,3-Dinitrobenzene in the aqueous phase were increased tremendously with increasing the molar ratio of sulfuric acid and nitric acid.The conversion of nitric acid increased signifucantly with the increase of sulfuric acid concentration.