This work deals with studying the mechanical properties specially fatigue behavior for high performance composite materials of poly ether ether ketone (PEEK)/glass fiber, which are used in Aircraft Industry. Two materials have been used: (PEEK natural) and (PEEK+30% glass fiber).To identify the type of (PEEK), infrared (FTIR) test has been conducted. X-ray test has been used to measure the (PEEK) crystalline ,also the tensile properties, impact strength and the fatigue test are performed.The results show that FTIR test peaks are for standard PEEK polymer and that GFRP increases the crystalline of (PEEK) material , while the tensile , impact and fatigue properties of (PEEK) decreases by adding GF to PEEK .