中文摘要：

从操作模式、切换目标、影响因素和数学描述四个方面对聚烯烃连续生产过程中产品的牌号切换问题进行了分析；讨论了最优牌号切换的研究特点和难点；回顾了近年来该领域的研究进展，探讨了未来的发展方向。

英文摘要：

The research on grade transition in continuous polyolefin production process is reviewed. The operation mode, grade transition objective, influence factors and mathematical descriptions of grade transition are presented, the characteristics and difficulties are described, the progress made in this area during the last decades is summarized, and the development trends in the future are discussed.