Abstarct: This thesis is introducing a new methodto observer baxsed sensor fault detection-withusing H- /H∞ index- on gas turbine model. In the new method,an enhanced PSO algorithm named of TPSO is introduced,which is used to solve the H- /H∞ problem. Also in this thesis the standard methods H2, H∞ and H- /H∞ are investigated and their analyzed results are compared with the proposed method.In all the named method, the goal is the elimination disturbance effect- and at the same time,intensification of fault effect- on the residual signal. The results show that, the proposed method is more successful to reach the goal and the residual signal is more robust to disturbance.