The traditional method can effectively improve the magnification，but additional devices are needed to determine the reflection times．Through the combination of a large plane mirror placed in a slant to the mirror of the optical lever，the number of reflections is accurately controlled to 2 levels，and the optical path is increased while an angle change is increased．Finally，the magnification is increased to 4 times of the traditional lever method．Theoretical analysis and experimental results show that the oblique double mirror method is used to measure the Young’s modulus of metal wire． The experimental results are in good agreement with the theoretical analysis，which verifies the effectiveness of the method and theory．In addition，the amplification factor is as high as 84．36 times in the limited space not more than 80 cm．