The cascade control has been broadly applied in chemical industry. The cascade structure have been an active area of research for many years. Cascade control is thought to be a good control structure when the dynamics of the outer loop is slower than the inner loop, but there is no a detailed report to show that and what will be happened when different dynamic structure is replaced. In this work, we begin from the single loop system to the cascade control. This work assesses the performance of disturbance rejection and setpoint tracking by setting different inner and outer dynamic.