This study presents thermogravimetric analyses (TGA) of CO2 co-gasification of petroleum coke with low sulphur (PC) and various types of biomass wastes including agricultural (rice husk (RH), rice stalk (RS) and cotton straw (CS)) and by-product wastes (saw dust (SD) and sugar cane bagasse (SCB)). Their reactivities, synergistic effect and kinetics were studied and compared in detail. The homogeneous model (HM) and shrinking core models (SCM) were applied to estimate the kinetic parameters. The results indicated that obvious synergistic effect was observed during the co-gasification of the blends. The PC gasification reactivity was significantly improved by the addition of biomass wastes. The model of R2 was found to be most suitable for the co-gasification. The activation energy of PC was decrease from 293.72 kJ/mol to 117.04 kJ/mol by the addition of SD. The co-gasification of PC and biomass waste is a promising way for the efficient utilization of PC and biomass wastes.