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In this study,we studied the separation progress of acetonitrile-ethyl acetate.Right now,Di Jiandong of Tianjin university has proposed a method for the separation of acetonitrile-ethyl acetate by heterogeneous batch azeotropic distillation; according to the difference of solubility that acetonitrile and ethyl acetate in the water,Ma Wenchan[1] proposed the method of liquid-liquid extractive which use water as extractive agent to separate acetonitrile-ethyl acetate,they all obtained ethyl acetate product,but the purity of product cannot meet requirement rigorously or with high energy consumption..In this paper,acetonitrile-ethyl acetate were separated by extractive distillation with mixed solvent[2-4].Currently,the solvent selection can be effectively handled by the assistance of the computer-aided molecular design (CAMD) approach.Computer-aided molecular design (CAMD) [5]approach was bring in for selecting extractive solvents.Firstly,based on Modfied UNIFAC method,the functional groups systematically are classified and pre-selected according to some rules,and then the automatic combination of groups is completed by using a graph algorithm.The group contribution methods are used to get the basic physical and thermal properties.The basic molecular library is formed by using several limited rules of basic physical properties.In the stage of solvent screening,the molecules in the basic molecular library are used directly.The candidate solvent molecules are obtained by using the solvent constraint and the appropriate solvent molecules can be determined by using the refined calculation or checking property library.Through carefully screen,we found DMF and EG are the most appropriate two for the separation of acetonitrile–ethyl acetate.Then,the separation of acetonitrile-ethyl acetate Azeotropic system was carried out through extractive distillation processes with N,N-dimethylformamide(DMF),glycol(EG) and DMF-EG mixture as solvents respectively.The effects of different operating conditions were studied,solvents,ratio of mixed solvent,solvent flow rate and reflux ratio were all included.It was found that the mixed solvent DMF-EG showed better separation effect than the single solvent.The better proportion of the mixed solvent was 3:7( the quality of DMF and EG ); when the solvent flow rate and reflux ratio increased,the separation effect improved; under the conditions that solvent flow rate was 20mL/min,reflux ratio was 2,quality fraction of ethyl acetate in the top product could reach 99.62%.