Sanghuangporus baumii is a traditional medicinal fungus that produces pharmacological terpenoids, but natural resources are insufficient for applications, and growth and development mechanisms are poorly understood. Combining metabolomic and transcriptomic analyses, we identified four terpenoid hormones and a central gene isopentenyl diphosphate isomerase (IDI) involved in growth and development. The importance of the four terpenoid hormones was further confirmed by exogenous hormones addition, we found that Cis-Zeatin (CZ) plays a major role in the mycelia stage, Trans-Zeatin (TZ) and Gibberellin A4 (GA4) are important in the primordia stage, GA4 is crucial for the fruiting bodies stage, and Abscisic Acid (ABA) may be a marker of maturity. Later, hormone content determination and qRT-PCR were used to verify the growth and development mechanism, and finally it was confirmed that IDI gene affects the content of terpenoid hormones content by regulating the transcript level of terpenoid biosynthesis genes, thus affecting the morphological changes of S. baumii. Our results illuminate the growth and development mechanisms of S. baumii, and may promote the breeding and utilisation of high-quality varieties.