Abstarct: This thesis describes the application of a robust fuzzy controller with robustness performance to the problem of a CSTR temperature control. Temperature control is important as many chemical reactions are sensitive to temperature for formation of desired product and reaction rates depend on the temperature. Since the CSTR is a nonlinear time-delay system, a linear model of the system is achieved around each equilibrium point using the linearization method. Then, baxsed on lyapunov approaches, such a linear feedback controller is designed to stabilize the nonlinear time-delay system and achieve the robust performance, and Takagi-Sugeno fuzzy system is also used to improve the robust performance. Besides, the effect of external disturbance on control performance ρ is attenuated to a minimum value. The sufficient conditions for the existence of such a controller are given in terms of linear matrix inequalities (LMIs) and the controller is derived trough the numerical solution of those LMIs.