Abstract: In 2020 and 2021, peach fruit with natural disease and decay were collected from orchards in Zhejiang Province. Then the fungal pathogens were isolated from the diseased spots and identified by morphological characteristics, molecular biological identification (rDNA-ITS sequence analysis) and pathogenicity detection. The antifungal effect of cinnamon essential oil on the fungal pathogens in vitro and in vivo were also investigated. The results showed that two fungal pathogens with strong pathogenicity were isolated, and identified as Monilinia fructicola and Rhizopus stolonifer, which caused brown rot and soft rot, respectively. Cinnamon essential oil inhibited the growth of M. fructicola and R. stolonifer, and the minimum inhibitory concentrations were 0.4 and 0.8 mL/L, respectively. M. fructicola was more sensitive to cinnamon essential oil. Cinnamon essential oil fumigation could reduce the disease incidence and lesion diameter of brown rot and soft rot of peach fruit caused by these two fungal pathogens. Therefore, cinnamon essential oil could be used as a natural fungicide to control fungal diseases of peach fruit.