An environmentally benign process has been established for the production of ibuprofen methyl ester, with ibuprofen and methanol as reactants, p-toluene sulfonic acid (PTSA) as catalyst, and glycerol as the adsorbent of water and the solvent of catalyst. The immiscibility of glycerol and ibuprofen methyl ester was exploited in this benign process. The chromatography was used to isolate the products. For whole the process, there is no effluent need to be discharged, neither the synthesis, nor the purification. The reaction conditions have been optimized as follows: the optimal molar ratio of reactants was ibuprofen: methanol: glycerol = 1:10.2:1.4; the optimal amount of PTSA was 1% (w/w) of ibuprofen; optimal reaction time was 4 h; optimum stirring speed was 300r/min. At the optimized condition, the conversion rate can be reached at 97.1%, the yield greater than 95%. Detected by LC/MS, the purity of ibuprofen methyl ester was 99.9%.