The coconversion of two kinds of waste materials, plastics and CO 2 , into a single value-added product is an innovative and challenging endeavor that simultaneously achieves the upcycling of plastic waste and reduces CO 2 emissions. Herein, we report a one-pot, two-step catalytic process for transforming polyesters, such as poly(glycolic acid), carbonate, and water, into sodium formate with a high yield of 79%, using a commercial Pd/C catalyst. This process involves the aqueous-phase reforming of polyester with water at 250-270 °C and the hydrogenation of NaHCO 3 at 150 °C, utilizing H 2 generated during the reforming process. Notably, no external H 2 or other reactive reagents are required. This strategy can be applied for the coconversion of poly(ethylene terephthalate) (PET), poly(butylene-adipate- co -terephthalate) (PBAT), and commercial biodegradable plastic bags with Na 2 CO 3 obtained from CO 2 capture via a NaOH solution, opening up a new path for "turning trash into treasure".