As a result of the development of the use of reinforced Composites with fibers in practical applications continuously, research aims to study the effect of proportion piroxide additives to unsaturated polyester resin on the tensile properties of the samples prepared from unsaturated polyester resin reinforced with glass fiber used in wind turbine blades manufacturing, and also studying the effect of for the application of heat treatment operations on the hardening of the unsaturated polyester and tensile properties after heat treatment process the application in order to improve the properties of these blades. Test samples were prepared containing ratios (1% - 1.5% - 2%) of methyl Etel ketone piroxide MEKP and test results showed that the best ratio at 1.5%. While the heat treatment results showed that the best values for tensile strength at break of the samples are treated to a time of / 48 hours /.