Promoting the development of electricity-carbon-green certificate market trading mechanism is an important measure to enhance the green and low-carbon transformation of energy system. The existing optimal allocation of resource capacity in industrial parks ignores the influence of market trading mechanism and flexible response of electrolytic aluminum load, and it is difficult to ensure the economy and applicability of the park allocation scheme. Therefore, an optimal allocation method of resource capacity in industrial parks considering electricity-carbon-green certificate market trading mechanism and electrolytic aluminum flexible load is proposed. Firstly, based on the energy demand and regulation characteristics of electrolytic aluminum production, the demand response model of electrolytic aluminum flexible load is established. Secondly, it studies the stepped carbon-green certificate trading mechanism to support energy conservation and carbon reduction in industrial parks; then, taking the annual investment-operation cost of the park as the optimization goal, considering the constraints of equipment investment, site limitation and equipment operation, the optimal allocation-scheduling model of resource capacity in the industrial park is established. Finally, the case analysis results show that the proposed configuration method can effectively reduce the annual cost of the park, take into account the efficient use of new energy in the park while reducing carbon emissions.