Alternaria alternata is the widespread pathogenic fungal that causes fruit postharvest illnesses. In the present research, the changes of A.alternata in sugar content as well as the transcription and protein responses after carvacrol treatment was studied. The results demonstrated that carvacrol treatment decreased the level of glycogen, total sugar, fructose and trehalose in A.alternata in a dose-depended manner. Combined transcriptome and 4D-DIA proteomics research revealed that 0.06 L/mL carvacrol administration accelerated the decomposition of A.alternata cell wall polysaccharides, hindered sucrose consumption, influenced the glycolysis pathway, and promoted carbohydrate decomposition related to stress resistance. The qRT-PCR results revealed that the effects of different concentrations of carvacrol on the expression of carbohydrate metabolism-related genes were essentially same in A.alternata. These findings reveal the inhibitory mechanism of carvacrol on A.alternata growth and the molecular response mechanism of A.alternata.