The bean deflection technology based on Micro-Electro-Mechanical System(MEMS)torsion mirror is one of the main technical schemes for Variable Optical Attenuators(VOA),which is liable to high Wavelength-Dependent Loss(WDL).This paper presents a design optimization scheme on the basis of analyzing the causes of the WDL.The experimental test results indicate that in the warelength range of 1.53~1.57μm and the attenuation range of 0~20dB,the measured maximum WDL is 0.21 dB,verifying the correctness of the theor...