<p>This paper developed an efficient microbial activator formula and conducted an in-depth study on its efficacy and mechanism in promoting the degradation of petroleum hydrocarbons in oil-contaminated soil. A 60-day microbial remediation experiment conducted on oily soil revealed that the microbial activators significantly boosted the activities of dehydrogenase and catalase, subsequently speeding up the degradation of petroleum hydrocarbons in the soil. The overall degradation rate reached as high as 71.23%, with the most significant degradation effect observed in asphaltenes, achieving a degradation rate of 93.98%. This was followed by aromatic hydrocarbons (90.45%), saturated hydrocarbons (84.39%), and asphaltenes (65%). Compared to traditional microbial stimulation methods, this activator demonstrated significant superiority. Microbial diversity analysis reveals that microbial activators can effectively activate microbial activity in soil targeting refractory petroleum hydrocarbon components. By comparing the changes in microbial community structure before and after the addition of microbial activators, we found that the activators promoted an increase in the abundance of microorganisms belonging to the Bacillota, Pseudomonadota, and Bacteroidetes, which have petroleum hydrocarbon degradation functions, and facilitated the evolution of microbial community structure towards a direction more conducive to petroleum hydrocarbon degradation. KEGG metabolic pathway analysis revealed that the degradation pathways for alkanes, aromatic hydrocarbons, and PAHs are primarily present in these bacterial phylum. This research not only clarifies the degradation mechanism but also supports future bioremediation efforts.</p>