Multi-walled carbon nanotubes/zinc ferrite (MWCNTs/ZnFe2O4) hybrid composites were successfully fabricated by a facile one-step solvothermal method. The structure, morphology, chemical composition and magnetic properties of the as-prepared composites were investigated in detail. It was observed that ZnFe2O4 microspheres were anchored on the surface of MWCNTs and the microspheres could act as the bridges to link the neighboring MWCNTs, which resulted in three-dimensional (3D) conductive networks formed in the hybrid composites. Furthermore, the effects of the size of microspheres and length of MWCNTs on the electromagnetic wave absorption performance of the hybrid composites were explored. Significantly, the optimized MWCNTs/ZnFe2O4 composite showed the minimum reflection loss of -55.5 dB at 13.4 GHz and effective absorption bandwidth (lower than - 10 dB) of 3.6 GHz with a thickness of only 1.5 mm. The excellent electromagnetic wave absorption performance was closely related to the well-designed 3D net-like structure and synergistic effect between MWCNTs and ZnFe2O4 microspheres in the composite. These results demonstrated that the MWCNTs/ZnFe2O4 hybrid composites could be attractive candidates for application in the electromagnetic wave absorption field.