The invention discloses an InGaAs detector integrating a polymer and nano material with a sub-wavelength structure. The structure of the InGaAs detector sequentially includes the polymer and nano material with the sub-wavelength structure, an InP buffer layer, an InGaAs absorbing layer, an InP cap layer, a SiO2 dielectric layer, a photosensitive chip indium column, a readout circuit indium columnand a readout circuit from top to bottom. The advantages of the invention are that: firstly, by integrating a high-refractive-index sub-wavelength material, the quantum efficiency of a traditional visible expanded InGaAs device can be further improved; secondly, compared with a traditional anti-reflection film material, the polymers and nano materials based on the sub-wavelength structure have a high degree of material and structural regulation, and further have high production efficiency and lower production costs; and thirdly, the sub-wavelength structure can reduce the complexity and size of a detection system and also has process compatibility with the detector.