On January 6, the price of phthalic anhydride in Jiangsu region remained strong and stable. The mainstream negotiation price for ortho-xylene-based products ranged from 5,900 to 6,150 yuan/ton, while the mainstream negotiation price for naphthalene-based products ranged from 5,600 to 5,850 yuan/ton. The operating rate of phthalic anhydride plants decreased, leading to a reduction in production. The domestic phthalic anhydride market had sufficient spot supply. The price of raw material ortho-xylene rose sharply, while the price of industrial naphthalene remained stable. The rising cost of phthalic anhydride provided stronger support. The downstream plasticizer market experienced a significant price increase, but the operating load of plasticizer enterprises decreased, leading to increased demand support for phthalic anhydride. Downstream industries made purchases based on rigid demand. In the later period, the phthalic anhydride market is expected to experience fluctuating price increases.