The operator-based right coprime factorization method is applied to deal with the design and control issues for the nonlinear feedback systems. In details, the general case of the unimodular operator M is discussed since the satisfaction of the Bezout identity AN + BD = M is necessary and important in the method of right coprime factorization, where a sufficient condition is proposed by which the Bezout identity can be satisfied, which means that the stability of the nonlinear systems is guaranteed. A simulation of temperature control in the Peltier actuated thermal process is given to show the validity of the proposed method.