Phosphorus (P) is a critical limiting nutrient in terrestrial ecosystems, and its bioavailability in soils is particularly important in influencing primary productivity and ecosystem carbon sequestration capacity. Mountain ecosystems are highly sensitive to climate changes and exhibit distinct responses to alterations in environmental conditions. The P bioavailability in mountain soils is thus a popular topic in ecological and environmental research, especially in the context of climate warming and increased atmospheric nitrogen (N) deposition. This review integrated a Meta-analysis method to synthesize findings of the response patterns and underlying mechanisms of soil P bioavailability to in situ simulated warming and N addition experiments in China’s mountain soils. This study found that single treatment of warming or nitrogen addition did not reduce the bioavailability of soil P, although there were still debates that were closely related to the initial environmental conditions of different ecosystems. Furthermore, the prospects of future research were provided, underscoring the necessity for long-term and multi-elevation in situ simulation experiments. These experiments are vital for understanding the variations in soil P bioavailability under the dual pressures of warming and N inputs. It is also essential to conduct controlled laboratory experiments to explore the effects of these factors on the transformation of soil P fractions across multiple spatial scales, such as landscape and ecosystem levels. Also, the molecular-level response mechanisms of soil P bioavailability to various climate change factors require further investigation. Additionally, there is a need to optimize the parameters in the P biogeochemical cycling models for predicting the effects of climate warming and varied atmospheric N deposition on soil P bioavailability in mountain ecosystems. These potential results will contribute to a far-reaching understanding of the processes and mechanisms of P biogeochemical cycling in mountains in the context of global climate change, which can become an important theoretical basis for the health and stability of mountain ecosystems.