Leucocalocybe mongolica (S. Imai) X.D. Yu & Y.J. Yao is a rare edible wild mushroom that is highly regarded in northeast Asia. Owing to its desirable flavour and health attributes, L. mongolica is collected unscrupulously by indigenous peoples and mycophiles. In addition, its habitat is under constant threat from human activities, and the wild production continues to decline as it cannot keep pace with the rate of harvest. To date, no cultivation techniques that can produce L. mongolica have been discovered; however, utilising fermentation technology offers a promising alternative approach. In this study, the nutrients and volatile components of the products arising from two fermentation techniques were evaluated. Significant differences were observed between the fruiting bodies and the... fermented products of L. mongolica with respect to protein, fat, and fibre contents. The results of gas chromatography-mass spectrometry showed that 21 volatile components likely account for the flavour of basidiocarps. The two fermentation methods exhibited significant differences in terms of the enrichment of the different volatile compounds. Comparison of the active components before and after solid-state fermentation on L. mongolica showed that the content of flavonoids, polysaccharides, triterpenoids, sterols, and phenols after solid-state fermentation was enhanced compared with the unleavened substrate. Given these results, solid-state fermentation technology for L. mongolica appears to be a promising alternative to cultivation.