Due to multiple factors such as environmental protection，safety，and shoreline resources，more and more large-scale petrochemical projects will be constructed on offshore islands in the future，and port shoreline utilization is becoming a key technical problem to be considered in such projects. Zhoushan green petrochemical base is the largest typical petrochemical project on offshore islands，with no land transportation connecting to the mainland. Based on the characteristics of offshore islands and petrochemical projects，this paper classifies and arranges the port shoreline through the study of natural conditions，public utilities，and project construction and operation requirements，puts forward the port shoreline utilization scheme for the large-scale petrochemical base of offshore islands，and summarizes key issues needing attention in similar projects.