This work aims to adjust the electromagnetic matching of graphene to achieve the best microwave absorption performance. Graphene oxide was prepared by improved Hummers method. The spindle-shaped ZnO rods wrapped by reduced graphene oxide (S-ZnO/r-GO) with heterostructure were synthesized by the hydrothermal method at 140 ℃ with Zinc nitrate hexahydrate, bis-hexamethylene triamine and graphene oxide as raw materials. The composition, morphology and microstructure of S-ZnO/r-GO were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The electromagnetic properties of S-ZnO/r-GO composite with different mass ratios were tested by vector network analyzer in the frequency range of 2~18 GHz through coaxial method, and the microwave reflection loss of the composite was calculated. The interlaced spindle-shaped ZnO rods with uniform shapes were wrapped with plenty crumpled r-GO sheets, thus constructing an interconnected 3D structure. Both the introduction of spindle-shaped ZnO and the construction of 3D structure significantly improved the electromagnetic characteristics and microwave response of S-ZnO/r-GO heterostructure in the frequency range of 2~18 GHz. A maximum reflection loss value of -40 dB was achieved at a thickness of 2.0 mm and a frequency of 14.8 GHz. The effective absorption bandwidth almost covered the whole Ku band. The composites of S-ZnO/r-GO exhibit prominent microwave absorption performance and wide effective absorption bandwidth and have certain application prospects.