Abstract: Through pot experiments and comparative inoculation trials with different carrier substrates, this study sampled at the end of the growth season (T₁) and the end of the rapid growth season (T₂) to assess the functional effect of the combination of an efficient phosphorus-soluble microbial strain during the growth of bamboo seedlings. Additionally, specific carriers for the microbial strains were constructed to observe and analyze their effects on seedling growth and the phosphorus nutrient environment in the soil. The results showed that both freeze-dried and liquid microbial agents from the synthetic microbial community significantly promoted seedling growth and nutrient accumulation. Among them, the liquid microbial agent had the best growth-promoting effect during the T₁ period, with root biomass and total nitrogen content in the roots significantly increasing by 103% and 15.65%, respectively, compared to the control(CK). The freeze-dried microbial agent showed the best growth-promoting effect during the T₂ period, with soil total nitrogen and available phosphorus content increasing significantly by 16.11% and 1105 times, respectively. The total biomass, as well as total nitrogen and total phosphorus content, increased significantly by 91.49%, 76.32%, and 122.58%, respectively, compared to CK. A 1:1 volume mixture of peanut shells and sugarcane bagasse was suitable as the carrier for the synthetic microbial community. One year after the application of the phosphate-solubilizing solid biofertilizer constructed with this carrier, the soil available phosphorus significantly increased by 408%. At the T₁ stage, the root and aboveground biomass of Moso bamboo seedlings increased by 8.7% and 41.9%, respectively, compared to the control(CK). At the T₂ stage, the root and aboveground biomass of Moso bamboo seedlings increased by 32.3% and 746%, respectively, compared to CK.