To reduce the reflection and improve the efficiency of multi-junction solar cell, a 4-layer antireflective coating with graded refractive index was designed for GaInP/GaAs/Ge triple-junction solar cell. Through adjusting the refractive indices of the different coatings, a 4-layer TiO2/ZrO2/A-SiO2/B-SiO2 antireflective coating with graded refractive index was successfully prepared by sol-gel dip-coating method. The results shown that the average reflectance of the triple-junction solar cell coated with the AR coatings decreased from 28.58% to 4.86 % while the maximum reflectance decreased from 46.35% to 15.45% in the wavelength range of 300~1 700 nm.