Driven by the goal of carbon neutrality, the construction of a new power system based on renewable energy represents a crucial step in realizing China's “dual-carbon” objective. However, the intermittency and uncertainty of wind and photovoltaic power generation have the effect of greatly increasing the demand for flexible regulation resources on the grid side, particularly in regard to the reliance on new energy storage technologies. To ensure the efficient allocation and management of new energy storage on the grid side and to reduce the waste of resources and environmental risks caused by decision-making errors, this paper presents an in-depth study on the optimal allocation model of new energy storage on the grid side considering the flexibility upward transmission from the user side based on Master-Salve game theory. The model is verified through actual arithmetic examples, and its scientific validity and effectiveness are demonstrated. The research provides theoretical support for improving the flexibility and stability of the grid side of the new power system, thereby facilitating its economic and efficient operation.