China leads the world in forest restoration; however, its overall biodiversity outcomes have been questioned. Using forest birds as indicators, we assessed biodiversity changes from 2000 to 2020 at a national scale. We found notable biodiversity benefits linked to forest expansion and improvement in forest structure, with 70% of species experiencing habitat expansion and mean species richness increasing by 2.721. Protection-focused and afforestation-dominated restoration programs both effectively enhanced biodiversity, with planted forests performing comparably to natural forests. Key factors facilitating this enhancement included tree cover and structural complexity. Our findings suggest that restoring planted forests in degraded landscapes can provide substantial biodiversity benefits, although this should incorporate mixed-culture to enhance structural complexity. This study highlights China’s achievements and risks in forest and biodiversity restoration, and provides insights for optimizing future restoration.