We evaluated the white matter (WM) of patients with newly diagnosed Parkinson’s disease (PD) with normal cognition (PD-NC) and mild cognitive impairment (PD-MCI) using diffusion tensor imaging (DTI) and free-water elimination DTI. Increased fractional anisotropy and decreased mean diffusivity and radial diffusivity in patients with PD suggested compensatory neural circuit reorganization. Changes were less extensive in WM areas previously considered vulnerable to MCI in the PD-MCI group than in the PD-NC group. Longitudinal analyses indicated neural compensation in the PD-NC group after 1 year. Overall, extensive and long compensatory mechanisms may be associated with preserved cognitive function in PD.