Propylene products from ethylene plant are used as raw materials for polypropylene plant. If the methanol in propylene products exceeds the standard, it will have a great impact on the production and operation of polypropylene plant. During the production of ethylene plant, there are many sources of methanol in the target product, including the methanol carried in raw materials, the alcohols produced from oxygenated compounds under high-temperature cracking conditions, and the methanol and propanol prepared by the plant for defrosting. These alcohols will eventually enter the propylene distillation system and affect the quality of propylene products. In this paper, the raw materials, quench water system and propylene distillation system are optimized and adjusted to improve the quality of propylene products and reduce its methanol content.