The insula, a cortical region that is thought to play a central role in this reward circuitry, has been implicated as an important role in the maintenance of nicotine addiction. However, it remains largely unclear about the alterations in white-matter tracts of insula circuits in nicotine addiction. Here, we further investigated the differences of insula white-matter tracts between smokers and nonsmokers. We found abnormal white matter tracts of insula subregions in smokers. These altered insula microstructural connectivity could interfere with the normal neural circuitry of reward processing, which might be the underlying neurobiology of nicotine addiction.