For the first time, the novel one-dimensional uniform polyaniline (PANI)/Ni0.5Zn0.5Fe2O4 (NZFO) hybrid nanorods were synthesized by an in situ polymerization approach with the assistance of ultrasound and magnetic field. Owing to the unique shape, structure, and chemical composition, the as-synthesized hybrid nanorods with different PANI/NZFO mass ratios possess adjustable magnetic properties, high-saturated magnetization, and coercivity. In addition, these hybrid nanorods present stronger reflection loss and a wider absorption band than pure NZFO. Especially, the hybrid nanorods containing 59 wt% NZFO exhibit excellent microwave absorption properties, with a maximum reflection loss (RL) of −27.5 dB observed at 6.2 GHz. And the widest absorption band (RL ≤ −10 dB) is 8.1 GHz, corresponding to a matching thin thickness of 2 mm. It is superior to the previously reported value of PANI/ferrite. Therefore, these PANI/NZFO hybrid nanorods may be candidates for lightweight, low-cost, broadband, and highly efficient microwave-absorbing materials.