<p>Forest reformation can improve productivity and ecological service functions of forest resources. Nonetheless, the influence of different ways of forest reformation on soil microbial communities is still a complex and controversial issue. In this study, we investigated the effects of supplementary seedling planting (hereafter referred to as “filling seedlings”) in secondary <i>Pinus massoniana</i> forests on soil bacterial community. We collected soil samples from original secondary <i>P. massoniana</i> forest and the forests filled with <i>P. massoniana</i> seedlings for 2, 4, and 6&#xa0;years, respectively. We found that filling seedlings in the secondary <i>P. massoniana</i> forests changed the bacterial community structure compared to the original secondary forests. Filling seedlings in secondary <i>P. massoniana</i> forest significantly decreased soil bacterial abundance from 2.12 × 10⁷ copies g⁻¹ soil to 8.91 × 10⁶ copies g⁻¹ soil (<i>n</i> = 3) after six years of reformation, a decrease by 58.0%. Acidobacteriota (34.96% averagely) was the dominant phylum and Xiphinematobacteraceae (5.76% averagely) was the dominant family in all <i>P. massoniana</i> forests in this study. Soil parameters such as soil pH, soil organic matter, NH₄⁺, NO₃^-, and total and soluble P were significantly correlated with the structure of bacterial communities (<i>p</i> &lt; 0.05). Moreover, the bacterial community structure and diversity changed over time during forest recovery. Our study demonstrated that filling seedlings in secondary <i>P. massoniana</i> forests could change soil bacterial community, which might in turn affect the nutrient cycling. This study provides scientific basis for managing low quality <i>P. massoniana</i> forests.</p>