To address the issues of high carbon emissions in integrated energy systems and the insufficient exploration of low-carbon potential of hydrogen, the flexible equipment such as the power to gas (P2G), the carbon capture, utilization and storage (CCUS), and the hydrogen-doped gas equipment (HDGE) are introduced. And an optimal dispatch model of integrated energy system with joint operation of P2G-CCUS-HDGE considering reward and penalty carbon trading is proposed. Firstly, a joint operation model of P2G-CCUS-HDGE is constructed, and a dynamic hydrogen-doped ratio operation mode is considered. Secondly, a reward and penalty stepped carbon trading mechanism is introduced to limit carbon emissions. Furthermore, aiming to minimize the total operational cost, an optimization dispatch model is established considering relevant constraints and solved using the GUROBI solver. Finally, by setting up multiple scenarios for comparison, the advantages of the proposed dispatch model in reducing total costs, decreasing carbon emissions, and improving renewable energy consumption are validated. Additionally, the impact of various hydrogen-doped ratios and carbon trading parameters on the economy and low-carbon performance of the system is explored, thus providing insights into the low-carbon economic dispatch of the system.