Understanding the relationships among bamboo growth, soil microbial community and phosphorus (P) fertilization may shed new light on the optimization of P application rate and ecological function of P nutrient in forest ecosystem. This study aimed to evaluate the impacts of P fertilizations (25 and 50 kg P ha−1) on Phyllostachys edulis (Moso bamboo) growths, soil nutrient contents and microbial properties at different altitudes (300 and 800 m) and to link Moso bamboo growths with abiotic and biotic factors. Compared with the blank control, P fertilizations alone generated negligible impacts on the increases of Moso bamboo biomass and soil available P contents. Bacterial and fungal community diversities kept relatively stable after P fertilizations. Contrastingly, relative to the control, 25 kg P ha−1 application significantly enhanced the relative abundance of Proteobacteria and changed bacterial community structure at low altitude. At low and high altitudes, 50 kg P ha−1 applications significantly increased the relative abundances of Ascomycota. The Moso bamboo growth might be stimulated by the increases of soil total nitrogen, available P, Proteobacteria and Ascomycota. Our results demonstrated that P fertilization alone significantly changed soil bacterial community structure but generated negligibly stimulating role in the increase of Moso bamboo biomass.