Under the deep implementation of the “Dual-Carbon” strategy, integrated energy systems (IESs) in industrial parks are increasingly taking on the dual roles of energy management and resource scheduling. However, demand response and optimal dispatch are often investigated separately, and coordinated supply-demand low-carbon optimization remains insufficient. To address this gap, a bi-level low-carbon optimization model for industrial-park IESs considering electricity-carbon demand response is proposed. A unified framework that couples demand response and optimal dispatch from the operator perspective is constructed. A dynamic multi-energy carbon-emission factor calculation method is developed, and a comprehensive demand response model integrating both electricity and carbon perspectives is established. A bi-level optimization model is further formulated, where carbon-emission factors are iteratively updated based on load adjustments to achieve solution convergence. Case studies show that, compared with the electricity-only demand response case, the total cost for operators is reduced by 4.15%, and carbon emissions are reduced by 14.3%.