Working capital, as a core element of company operation and management, plays an important role in various aspects of the company, particularly in activities such as production, ordering, financing, etc. However, internal and external uncertainties, as well as various time cycles, constitute a complex operational environment that will severely affect the capital level of the node companies in the supply chain finance system, and thus cause serious disruptions to the system stability. Therefore, this paper aims to propose an effective capital equilibrium strategy to achieve the switching control of system capitals, thereby reducing system costs and improving system stability. Considering a two-echelon supply chain finance system, this paper designs a capital equilibrium switching strategy based on the T-S fuzzy theory to achieve the system capital equilibrium. The paper also proves the effectiveness and scientific validity of the proposed method, and compares and analyzes the differences of capital equilibrium strategies under fuzzy robust control and robust control through five numerical simulations. The research results show that fuzzy robust control can better suppress the interference of uncertainty on the switching of capital equilibrium strategy, and make the system more stable.