Abstract: An ideal mathematic model for the separation process of SMB, based on the theory of mass balance, was developed. According to the theory of Massimo's triangle, the effect of main operating parameters on the SMB performance characterized by purity and recovery was studied. Then the operation condition for a special separation object was optimized by computer simulation, and under the guidance of which, the operation of the SMB pilot was carried out. The result is satisfactory, which shows that the simplified model is helpful to operation optimization, parameter design and separation performance predict.