Young’s modulus of biaxially oriented polypropylene(BOPP) films prepared with homemade film stretcher was investigated, which can be used to indicate the softness of films. It was found that the modulus of films was decreased by about 69% as the content of polyethylene(PE) added into polypropylene(PP) reached 30%. Also, increasing draw temperature can induce lower stress level during stretching, which may lead to the formation of crystals with low orientation level and thus decreased modulus of films. Based on laboratory study, BOPP films produced on commercial line were studied by differential scanning calorimetry(DSC), wide and small-angle X-ray scattering(WAXS, SAXS) with varying contents of PE. SAXS results show that the crystals are oriented in both machine direction(MD) and transverse direction(TD), and the crystals are more oriented in TD than MD according to the WAXS results for all films. Also, the orientation parameter of crystal along TD increases from 0.68 to 0.83 as the contents of PE increase from 0% to 25%. Meanwhile, the modulus of films in MD declines with increase of PE contents generally, improving the film softness. Orientation of crystals is thus an effective structure parameter to adjust the film softness. The relationship of processing-structure-property is also established. Young’s modulus of biaxially oriented polypropylene (BOPP) films prepared with homemade film stretcher was investigated, which could be used to indicate the softness of films. It was found that the modulus of films was decreased by about 69% as the content of polyethylene (PE increasing draw temperature can induce lower stress level during stretching, which may lead to the formation of crystals with low orientation level and thus decreased modulus of film. Based on laboratory study, BOPP films produced on commercial line were studied by differential scanning calorimetry (DSC), wide and small-angle X-ray scattering (WAXS, SAXS) with varying contents of PE. SAXS results show that the crystals are oriented in both machine direction transverse direction (TD), and the crystals are more oriented in TD than MD according to the WAXS results for all films. Also, the orientation parameter of crystal along TD increases from 0.68 to 0.83 as the co ntents of PE increase from 0% to 25%. The modulus of films in MD declines with increase of PE contents generally, improving the film softness. Orientation of crystals is thus effective structure parameter to adjust the film softness. processing-structure-property is also established.