In-Sn/rGO composites with different In doping contents were prepared by sol–gel method combined with high temperature heat treatment using nano-SnO₂ as precursor. The effects of In content on the micro-structure, phase composition, defect degree, dielectric constant, electrical conductivity and dielectric properties of the composites were investigated. The results show that the introduction of In has no significant effect on the micro-structure and the phase composition, only slightly reducing the degree of defects in the composite material. With the increase of In content， the dielectric constant and electrical conductivity of the composite increase first and then decrease. The dielectric properties of In-Sn/rGO composite are best when the In doping mass fraction is 1.0%, the reflection loss value is –51.16 dB, the corresponding absorption frequency is 8.72 GHz, and the effective absorption bandwidth is 3.60 GHz.