SiC nanowire/acrylic resin (SiCnw/ACR) composites with broadband electromagnetic (EM) absorption capabilities were fabricated by a novel procedure using 3D stereolithography (3D-SL) printing technology. The EM absorption abilities of the composites can be adjusted by tuning the SiCnw content and the thickness of the printing layer. When the SiCnw content is 3 wt% and the thickness of the printing layer is 25 mu m-50 mu m, the SiCnw/ACR composite has an optimally broad effective absorption bandwidth (EAB) and a high efficiency for EM absorption, whether assessing the C, X or Ku band, because of the high dielectric loss and proper impedance matching between the materials and free space. In the C band (4-8 GHz), the EAB reaches 2.9 GHz, and the reflection loss (RL) reaches - 34.1 dB; in the X band (8-12 GHz), the EAB reaches 4 GHz, which covers the entire X band, and the RL reaches - 34.5 dB; in the Ku band (12-18 GHz), the EAB exceeds 6 GHz, which covers the whole Ku band, and the RL reaches - 34.7 dB. This research is of great importance to the rapid preparation of parts, shells or devices with arbitrarily complex shapes and high efficiency broadband EM absorption abilities.