A double-lens structure and a method for fabricating the same are provided. The double-lens structure includes a first lens structure formed of a color filter layer having a first refractive index and a second lens structure formed of a micro-lens material layer having a second refractive index and disposed on the first lens structure. The first refractive index of the color filter layer is different from the second refractive index of the micro-lens material layer. An incident light enters the second lens structure and then passes through the first lens structure. Further, a method for fabricating the double-lens structure is also provided.