Abstarct: Increase of nonlinear loads and the use of plasticizers near the inverter, the voltage and current harmonics and power quality have increased dramatically showed the risk. Failure to Harmvnyk¬Ha increased motor losses and damage to the isolation transformer and an error in measurement equipment and reduce the useful life of electrical equipment evenly. To improve the situation and being located in the harmonic limit set by the authoritative standards such as IEEE Std 519-1992 They are the strategies employed include the use of passive filters. In this thesis attempts to present model of passive filters with respect to investigations and An overview of the work done in conjunction with the optimization of passive filters, and then to design an optimal RLC filter parameters bt Using genetic algorithms and present an optimal filter is the price and the size of the reducing power losses and Harmonics So that by choosing appropriate parameters, system performance, and conduct more in our control range and its prediction and then try to introduce a new structure to suppress further Harmonics and THD. undifine structure without increasing the size and efficiency thereby increasing their price comes and elements eliminate more Harmonics in eliminating frequency comes close to the performance of the system.