Abstract: As the proportion of renewable energy increases, the combination of its intermittent output and the uncertainty of demand on the consumer side has led to a significant rise in the instability of the power system. Load aggregators have emerged as a new market player capable of consolidating small and medium-sized shippable loads; however, the current incentive mechanisms are inadequate, which has constrained the enthusiasm of end users to participate in demand response. This paper proposes a three-layer optimization model for grid companies to address the issue of effectively incentivize load aggregators and end-users to participate in power demand response with cost constraints. By analyzing the cost-benefit relationships among grid companies, load aggregators, and users, value functions are established for each party. A three-layer optimization framework is developed with load aggregators as the intermediary, grid companies as the upper level and users as the lower level. Finally, an algorithm with the primary objective of maximizing the benefit of grid companies is proposed to solve the model. Experimental results demonstrate that the proposed approach not only ensures economic benefit for all participants, but also promotes energy conservation and emissions reduction effectively to reduce operational cost for grid companies, proving theoretical and practical significance.