With heavier and deteriorated cracking feedstocks, an 800 kt/a steam cracking unit faces two major challenges, i.e., the high-load operation control of heavy component separation towers and the increased fouling rates due to the heavier feedstock. This paper analyzes the impact of long-term high-load operation of heavy component separation towers and the material polymerization and fouling on the normal operation of the process system. Some optimization measures are proposed from the aspects of process operation optimization, equipment maintenance strategies and design debottlenecking modifications to ensure the long-term safe production of the heavy component separation towers in steam cracking unit.