Abstract: A series of polyetheretherketone (PEEK) films were prepared by an extrusion casting method, and their natural characteristics, optical properties, mechanical performance were investigated by means of tensile tester, differential scanning calorimeter, UV spectrophotometer, and light transmittance & haze meter. The results indicated that the transmittance of the PEEK films decreased with an increase of the degree of crystallinity, and there was little effect of tensile rate on tensile strength and elongation at break. The yield strength increased with an increase in tensile speed significantly. Moreover, The tensile strength trend to increase as the speed of the casting roll increased. The PEEK films achieved the tensile strength of 203 MPa after biaxial stretching, and their anti-ultraviolet performance was also improved with the increase of film thickness and degree of crystallinity.