The invention discloses a preparation method of a multiple quantum well structure for a photoelectric device. The multiple quantum well structure comprises n quantum well structures which are overlapped in sequence, and each quantum well structure is formed by sequential growth of potential well layers and potential barriers, wherein the growth of each potential well layer comprises the following steps: 1, first growing an NixGa1-xN potential well layer, wherein x is more than 0.1 and less than 0.45; 2, growing a GaN insert layer; and 3, growing the InxGa1-xN potential well layer, wherein x is more than 0.1 and less than 0.45. When the potential well layer grows, one or more than two of GaN insert layers with energy band width different from that of the InxGa1-xN potential well layer and an In treatment layer grow alternately. On the one hand, the In treatment layer can stabilize the structure of the InxGa1-xN, ensures the stability of quantum well components, and controls the stability and consistency of wavelength; on the other hand, the GaN insert layer disturbs the energy band structure of a quantum well region to improve the composite rate of electron hole pairs, so that the internal quantum efficiency of device illumination is improved, and as the brightness is improved, the life test performance of the device can be improved.