This paper investigates the problems of robust Hinfin performance analysis and control synthesis for linear systems, having polytopic type of uncertainties, via the parameter-dependent Lyapunov functions. First, via employing a descriptor model transformation of the system, a Hinfin performance criterion in terms of linear matrix inequalities is derived. This Hinfin performance criterion can be adopted for robust controller synthesis as shown. The H infin performance criterion is applied to design flight tracking controller for aircraft dynamic systems with multiple operating points. These results illustrate the effectiveness of the proposed approach