Thelephora ganbajun Zang, a rare wild macrofungus, has significant culinary and medicinal value. However, it also has a high cost attributed to its inability to achieve artificial cultivation and its strict environmental requirements. To reveal the intricacies of its development, we conducted a comprehensive analysis of the proteome and metabolome in three pivotal developmental stages: the mycelium, the primordium, and the fruiting body. In our investigation, genes exhibiting various expression levels across multi-omics analyses were identified as potential candidates implicated in growth, development, or metabolic regulation. The aim of this study was to provide a clearer direction for understanding the fundamental metabolic activities and growth stages of this species. Label-free proteomic sequencing revealed a critical juncture in ectomycorrhiza formation, particularly during the transition from the mycelium to the primordium. Secreted proteins, signaling proteins, membrane proteins, and proteins with unidentified functions were rapidly synthesized, with certain amino acids contributing to the synthesis of proteins involved in signaling pathways or hormone precursor substances. In the metabolomics analysis, the classification of secondary metabolites revealed a noteworthy increase in lipid substances and organic acids, contributing to cell activity. The early mycelial development stage exhibited vigorous cell metabolism, contrasting with a decline in cell division activity during fruiting body formation. In our findings, the integration of metabolomic and transcriptomic data highlighted the potential key role of folate biosynthesis in regulating early ectomycorrhiza development. Notably, the expression of alkaline phosphatase and dihydrofolate synthase genes within this pathway was significantly up-regulated in the mycelium and fruiting body stages but down-regulated in the primordium stage. This regulation primarily influences dihydrofolate reductase activity and B vitamin synthesis.