The oil vapor will evaporate from the oil ship in the course of loading of volatile oil and oil products on the ship. The environmental impact statement of engineering projects requests to take appropriate measures to recycle the oil vapor and reduce the environmental pollution. But the measures of oil vapor recovery are not perfect at present. Taking the “Product Port Project for Petro China/PDVSA Joint Venture Guangdong Petrochemical 20 MMTPA Refinery Project” for example, this paper analyzes the main design points of oil vapor recovery technology on terminal.