Objectives: Although a variety of therapeutic techniques have been suggested for patients with unilateral adductor vocal fold paralysis (UAVFP), they were not aimed specifically at determining the efficacy of early intervention for these patients. The purposes of this study are to explore a protocol of voice therapy and to investigate its efficacy in voice therapy for patients with early UAVFP. A 12-week planned voice therapy protocol, including vocal function exercise, hard attack, and resonance voice therapy, was given to 10 patients within 6 months of initial diagnosis. Additionally, nine patients diagnosed with UAVFP within 6 months served as controls. Methods: Multidimensional evaluations of voice function were obtained for statistical analyses. Results: Compared to a control group, the experimental group receiving voice therapy exhibited significant improvement in the following: (1) glottal closure; (2) voice quality of grade, breathiness, monotone, and resonance; (3) acoustic measurements of jitter, shimmer, and noise-to-harmonic ratio; (4) aerodynamics measurements of maximum phonation time, phonation threshold pressure, and phonation quotient; and (5) Voice Handicap Index of functional subscale. Conclusion: This prospective study established an effective protocol of early intervention of voice therapy in patients with UAVFP and demonstrated its efficacy in data on laryngeal physiology, voice quality, voice stability, voice efficiency, and communication function.