High value-added utilization of plastic waste has historically been a problem, which has driven researchers to make long-term and unremitting efforts to tackle it. High-performance carbon based solid acid (CSA) was prepared from polyvinyl chloride (PVC) and polyethylene (PE) in different proportions. The small amount of chlorine is still residual on the edge of graphitic carbon sheets after co-carbonization and sulfonation. Strong electronegative -Cl group and the high-density phenolic -OH group, double-adsorption group, are covalently bonded to the edges of the graphitic carbon sheets, contributing to the decrystallization of cellulose to a large extent. Meanwhile, PVC and PE-derived CSAs have significantly higher -SO3 H group density than PVC-derived CSA and cellulose-derived CSA. These are obviously beneficial to the improvement of hydrolysis activity, which can be attributed to structural optimization caused by co-carbonization PVC and PE. The CSA with a mixture of 80% proportions has great catalytic activity and repeatability.