The excitation of brittleness is the key to overall managerial difficulties，and brittle risk control is the important leverage to improve the security of management system． Based on the path analysis of brittle risk spread in firm’s business system，the basic state-dependent model and modified control model considering growth rate and decline rate of business are put forward，and the effect of three strategies such as immunization，isolation and integrated control is evaluated and compared． In addition，the existence of periodic solutions of improved model and optimal cycle control strategy are discussed． The results show that different control strategies can provide the same results in terms of risk control． Under the same objective，the total cost of integrated control strategy is the lowest，while the total cost of immunization strategy and isolation strategy depends on the initial conditions and critical parameters． Moreover，the best option is to implement a cyclical comprehensive control strategy when none of the strategies can achieve the goal．