The aim of this work is to determine the influence of one-year shading on soil physical and chemical attributes, moss leaf and root traits, and bacterial and fungal communities of the moss phyllosphere and rhizoplane on the subtropical plateau in Southwest (SW) China, as well as to explore the biological drivers of moss traits. Results show that shading significantly reduces the moss root aluminum content (p = 0.032). Five bacterial and nine fungal lineages are significantly enriched on moss phyllosphere under shading treatment, nine bacterial and two fungal lineages on moss phyllosphere under nonshading treatment, sixteen bacterial and eight fungal lineages on moss rhizoplane under shading treatment, and seventeen bacterial and fourteen fungal lineages on moss rhizoplane under non-shading treatment [linear discriminant analysis scores (LDA) ≥ 4, p < 0.05]. The relative abundance of the moss phyllosphere Granulicella genus (r = -0.74, p = 0.014) is inversely related to the moss root aluminum content, while that of the moss phyllosphere Saitozyma genus (r = 0.72, p = 0.018) is positively related. This study emphasizes the importance of the epiphytic microbiome in shaping moss traits in subtropical moss production in China.