On January 12, the price of phthalic anhydride in East China showed a strong upward trend. The mainstream quotation for ortho-xylene-based phthalic anhydride in the market was 6,100–6,350 yuan/ton, while the price of naphthalene-based phthalic anhydride ranged from 5,700 to 6,050 yuan/ton. The price of industrial naphthalene fluctuated and stabilized, while the price of ortho-xylene rose significantly, leading to an increase in the cost of phthalic anhydride. Downstream, the plasticizer market remained strong and stable, with plasticizer manufacturers reducing their equipment operating rates. Downstream demand for rigid procurement persisted, and phthalic anhydride was primarily purchased on an as-needed basis. Demand support for phthalic anhydride remained, while phthalic anhydride manufacturers slightly reduced their equipment operating rates. Supply of phthalic anhydride was sufficient, and inventory levels were low. It is expected that the phthalic anhydride market will continue to show a strong upward trend in the future.