Under the dual-carbon objective, a virtual power plant (VPP) with multi-energy coupling and cooperative operation can effectively improve the economic efficiency of the system. In order to reduce the carbon emissions of VPPs and solve the problem of benefit distribution among market players, a collaborative optimization model among multi-energy VPPs considering stepped carbon trading is proposed. Firstly, based on a tiered carbon trading mechanism and considering the constraints of VPP components, a VPP model participating in the carbon trading market is established. Secondly, a multi-energy-coupled VPP group optimization model based on Nash bargaining theory is constructed. In this paper, three multi-energy-coupled VPPs are selected for case analysis, demonstrate that the proposed optimization method can improve the revenue of each VPP and the overall revenue while balancing fairness and environmental concerns.