The catalytic CO oxidation on platinum group metals exhibits complex intrinsic nonlinear properties, such as reaction rate catastrophe, bistability, and hysteresis. These intrinsic nonlinear properties depend on the inherent stability and self-organization mechanism of the chemical reaction. A corresponding phenomenon is a path-dependent input-output relationship between the CO oxidation reaction rate and the control parameters. The traditional linear control method for these systems has an inherently unstable mechanism that can give rise to the oscillation of the chemical reaction rate and the instability of the control system. However, the previous application of ordinary nonlinear switching control faces a large disturbance at the initial moment of switching, which will affect the dynamic performance and stability of the control system. For this reason, a smooth switching control method based on the integral initial value reset was proposed. The results show that the proposed method can provide a smooth switching control of CO oxidation reaction rate, and thus the dynamic performance of the control system is improved.