Abstract: In order to reduce the content of formaldehyde and heavy metal cadmium in Lentinus edodes, the effect of different acid pretreatments on the removal of formaldehyde and cadmium content in Lentinus edodes was studied, and the removal method was optimized orthogonally. The results showed that the removal rate of formaldehyde and cadmium from Lentinus edodes was the highest under the conditions of pH4.5, solid-liquid ratio 1:4 g/mL, and shaking temperature 35 ℃, which were 88.06% and 79.57%, respectively. Finally, gas chromatography-ion mobility mass spectrometry (GC-IMS) was used to determine the effect of lactic acid pretreatment on volatile flavor compounds of Lentinus edodes. The results showed that there were 28 volatile substances in Lentinus edodes samples, including 9 kinds of aldehydes, 8 kinds of ketones, 6 kinds of alcohols, 4 kinds of esters and 1 kind of acid compounds. The lactic acid pretreatment dried Lentinus edodes showed an increase in 2-pentanone, cyclohexanone and gamma-butyrolactone and a significant reduction in 3-octanone and butyraldehyde. In dried Lentinus edodes, pungent flavours such as onion and pungency were reduced, and creamy and fruity aromas were increased, with a strong, richly layered odour.